diff --git a/include/zephyr/posix/mqueue.h b/include/zephyr/posix/mqueue.h
index 40db073337490..d3fb90ca72110 100644
--- a/include/zephyr/posix/mqueue.h
+++ b/include/zephyr/posix/mqueue.h
@@ -7,8 +7,9 @@
 #ifndef ZEPHYR_INCLUDE_POSIX_MESSAGE_PASSING_H_
 #define ZEPHYR_INCLUDE_POSIX_MESSAGE_PASSING_H_
 
+#include <time.h>
+
 #include <zephyr/kernel.h>
-#include <zephyr/posix/time.h>
 #include <zephyr/posix/fcntl.h>
 #include <zephyr/posix/signal.h>
 #include <zephyr/posix/sys/stat.h>
diff --git a/include/zephyr/posix/posix_features.h b/include/zephyr/posix/posix_features.h
index a78b4c2a8d941..935e3ce2fe1ea 100644
--- a/include/zephyr/posix/posix_features.h
+++ b/include/zephyr/posix/posix_features.h
@@ -56,10 +56,6 @@
 #define _POSIX_CLOCK_SELECTION _POSIX_VERSION
 #endif
 
-#ifdef CONFIG_POSIX_CPUTIME
-#define _POSIX_CPUTIME _POSIX_VERSION
-#endif
-
 #ifdef CONFIG_POSIX_FSYNC
 #define _POSIX_FSYNC _POSIX_VERSION
 #endif
@@ -90,10 +86,6 @@
 #define _POSIX_MESSAGE_PASSING _POSIX_VERSION
 #endif
 
-#ifdef CONFIG_POSIX_MONOTONIC_CLOCK
-#define _POSIX_MONOTONIC_CLOCK _POSIX_VERSION
-#endif
-
 /* #define _POSIX_PRIORITIZED_IO (-1L) */
 
 #ifdef CONFIG_POSIX_PRIORITY_SCHEDULING
@@ -161,10 +153,6 @@
 /* #define _POSIX_THREAD_ROBUST_PRIO_INHERIT (-1L) */
 /* #define _POSIX_THREAD_ROBUST_PRIO_PROTECT (-1L) */
 
-#ifdef CONFIG_POSIX_THREAD_SAFE_FUNCTIONS
-#define _POSIX_THREAD_SAFE_FUNCTIONS _POSIX_VERSION
-#endif
-
 /* #define _POSIX_THREAD_SPORADIC_SERVER (-1L) */
 
 #ifdef CONFIG_POSIX_THREADS
@@ -177,10 +165,6 @@
 #define _POSIX_TIMEOUTS _POSIX_VERSION
 #endif
 
-#ifdef CONFIG_POSIX_TIMERS
-#define _POSIX_TIMERS _POSIX_VERSION
-#endif
-
 /* #define _POSIX_TRACE (-1L) */
 /* #define _POSIX_TRACE_EVENT_FILTER (-1L) */
 /* #define _POSIX_TRACE_INHERIT (-1L) */
diff --git a/include/zephyr/posix/posix_limits.h b/include/zephyr/posix/posix_limits.h
index 4441f9497cf35..9c225b4b4d4e0 100644
--- a/include/zephyr/posix/posix_limits.h
+++ b/include/zephyr/posix/posix_limits.h
@@ -7,6 +7,8 @@
 #ifndef ZEPHYR_INCLUDE_ZEPHYR_POSIX_POSIX_LIMITS_H_
 #define ZEPHYR_INCLUDE_ZEPHYR_POSIX_POSIX_LIMITS_H_
 
+#if defined(_POSIX_C_SOURCE) || defined(__DOXYGEN__)
+
 /*
  * clang-format and checkpatch disagree on formatting here, so rely on checkpatch and disable
  * clang-format since checkpatch cannot be selectively disabled.
@@ -122,4 +124,6 @@
 
 /* clang-format on */
 
+#endif
+
 #endif /* ZEPHYR_INCLUDE_ZEPHYR_POSIX_POSIX_LIMITS_H_ */
diff --git a/include/zephyr/posix/posix_time.h b/include/zephyr/posix/posix_time.h
new file mode 100644
index 0000000000000..0b9a8c840cc0c
--- /dev/null
+++ b/include/zephyr/posix/posix_time.h
@@ -0,0 +1,195 @@
+/*
+ * Copyright The Zephyr Project Contributors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_ZEPHYR_POSIX_POSIX_TIME_H_
+#define ZEPHYR_INCLUDE_ZEPHYR_POSIX_POSIX_TIME_H_
+
+#if defined(_POSIX_C_SOURCE) || defined(__DOXYGEN__)
+
+#include <stddef.h>
+
+#include <zephyr/sys/clock.h>
+#include <zephyr/toolchain.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* clock_t must be defined in the libc time.h */
+/* size_t must be defined in the libc stddef.h */
+/* time_t must be defined in the libc time.h */
+
+#if !defined(_CLOCKID_T_DECLARED) && !defined(__clockid_t_defined)
+typedef unsigned long clockid_t;
+#define _CLOCKID_T_DECLARED
+#define __clockid_t_defined
+#endif
+
+#if !defined(_TIMER_T_DECLARED) && !defined(__timer_t_defined)
+typedef unsigned long timer_t;
+#define _TIMER_T_DECLARED
+#define __timer_t_defined
+#endif
+
+#if !defined(_LOCALE_T_DECLARED) && !defined(__locale_t_defined)
+#ifdef CONFIG_NEWLIB_LIBC
+struct __locale_t;
+typedef struct __locale_t *locale_t;
+#else
+typedef void *locale_t;
+#endif
+#define _LOCALE_T_DECLARED
+#define __locale_t_defined
+#endif
+
+#if !defined(_PID_T_DECLARED) && !defined(__pid_t_defined)
+typedef int pid_t;
+#define _PID_T_DECLARED
+#define __pid_t_defined
+#endif
+
+#if defined(_POSIX_REALTIME_SIGNALS)
+struct sigevent;
+#endif
+
+/* struct tm must be defined in the libc time.h */
+
+#if __STDC_VERSION__ >= 201112L
+/* struct timespec must be defined in the libc time.h */
+#else
+#if !defined(_TIMESPEC_DECLARED) && !defined(__timespec_defined)
+typedef struct {
+    time_t tv_sec;
+    long   tv_nsec;
+} timespec_t;
+#define _TIMESPEC_DECLARED
+#define __timespec_defined
+#endif
+#endif
+
+#if !defined(_ITIMERSPEC_DECLARED) && !defined(__itimerspec_defined)
+struct itimerspec {
+       struct timespec it_interval;
+       struct timespec it_value;
+};
+#define _ITIMERSPEC_DECLARED
+#define __itimerspec_defined
+#endif
+
+/* NULL must be defined in the libc stddef.h */
+
+#ifndef CLOCK_REALTIME
+#define CLOCK_REALTIME ((clockid_t)SYS_CLOCK_REALTIME)
+#endif
+
+#ifndef CLOCKS_PER_SEC
+#if defined(_XOPEN_SOURCE)
+#define CLOCKS_PER_SEC 1000000
+#else
+#define CLOCKS_PER_SEC CONFIG_TICKS_PER_SECOND
+#endif
+#endif
+
+#if defined(_POSIX_CPUTIME) || defined(__DOXYGEN__)
+#ifndef CLOCK_PROCESS_CPUTIME_ID
+#define CLOCK_PROCESS_CPUTIME_ID ((clockid_t)2)
+#endif
+#endif
+
+#if defined(_POSIX_THREAD_CPUTIME) || defined(__DOXYGEN__)
+#ifndef CLOCK_THREAD_CPUTIME_ID
+#define CLOCK_THREAD_CPUTIME_ID ((clockid_t)3)
+#endif
+#endif
+
+#if defined(_POSIX_MONOTONIC_CLOCK) || defined(__DOXYGEN__)
+#ifndef CLOCK_MONOTONIC
+#define CLOCK_MONOTONIC ((clockid_t)SYS_CLOCK_MONOTONIC)
+#endif
+#endif
+
+#ifndef TIMER_ABSTIME
+#define TIMER_ABSTIME SYS_TIMER_ABSTIME
+#endif
+
+/* asctime() must be declared in the libc time.h */
+#if defined(_POSIX_THREAD_SAFE_FUNCTIONS) || defined(__DOXYGEN__)
+char *asctime_r(const struct tm *ZRESTRICT tm, char *ZRESTRICT buf);
+#endif
+/* clock() must be declared in the libc time.h */
+#if defined(_POSIX_CPUTIME) || defined(__DOXYGEN__)
+int clock_getcpuclockid(pid_t pid, clockid_t *clock_id);
+#endif
+#if defined(_POSIX_TIMERS) || defined(__DOXYGEN__)
+int clock_getres(clockid_t clock_id, struct timespec *ts);
+int clock_gettime(clockid_t clock_id, struct timespec *ts);
+#endif
+#if defined(_POSIX_CLOCK_SELECTION) || defined(__DOXYGEN__)
+int clock_nanosleep(clockid_t clock_id, int flags,
+		    const struct timespec *rqtp, struct timespec *rmtp);
+#endif
+#if defined(_POSIX_TIMERS) || defined(__DOXYGEN__)
+int clock_settime(clockid_t clock_id, const struct timespec *ts);
+#endif
+/* ctime() must be declared in the libc time.h */
+#if defined(_POSIX_THREAD_SAFE_FUNCTIONS) || defined(__DOXYGEN__)
+char *ctime_r(const time_t *clock, char *buf);
+#endif
+/* difftime() must be declared in the libc time.h */
+#if defined(_XOPEN_SOURCE) || defined(__DOXYGEN__)
+struct tm *getdate(const char *string);
+#endif
+/* gmtime() must be declared in the libc time.h */
+#if __STDC_VERSION__ >= 202311L
+/* gmtime_r() must be declared in the libc time.h */
+#else
+#if defined(_POSIX_THREAD_SAFE_FUNCTIONS) || defined(__DOXYGEN__)
+struct tm *gmtime_r(const time_t *ZRESTRICT timer, struct tm *ZRESTRICT result);
+#endif
+#endif
+/* localtime() must be declared in the libc time.h */
+#if __STDC_VERSION__ >= 202311L
+/* localtime_r() must be declared in the libc time.h */
+#else
+#if defined(_POSIX_THREAD_SAFE_FUNCTIONS) || defined(__DOXYGEN__)
+struct tm *localtime_r(const time_t *ZRESTRICT timer, struct tm *ZRESTRICT result);
+#endif
+#endif
+/* mktime() must be declared in the libc time.h */
+#if defined(_POSIX_TIMERS) || defined(__DOXYGEN__)
+int nanosleep(const struct timespec *rqtp, struct timespec *rmtp);
+#endif
+/* strftime() must be declared in the libc time.h */
+size_t strftime_l(char *ZRESTRICT s, size_t maxsize,
+       const char *ZRESTRICT format, const struct tm *ZRESTRICT timeptr,
+       locale_t locale);
+#if defined(_XOPEN_SOURCE) || defined(__DOXYGEN__)
+char *strptime(const char *ZRESTRICT s, const char *ZRESTRICT format, struct tm *ZRESTRICT tm);
+#endif
+/* time() must be declared in the libc time.h */
+#if defined(_POSIX_TIMERS) || defined(__DOXYGEN__)
+int timer_create(clockid_t clockId, struct sigevent *ZRESTRICT evp, timer_t *ZRESTRICT timerid);
+int timer_delete(timer_t timerid);
+int timer_getoverrun(timer_t timerid);
+int timer_gettime(timer_t timerid, struct itimerspec *its);
+int timer_settime(timer_t timerid, int flags, const struct itimerspec *value,
+		  struct itimerspec *ovalue);
+#endif
+
+#if defined(_XOPEN_SOURCE) || defined(__DOXYGEN__)
+extern int    daylight;
+extern long   timezone;
+#endif
+
+extern char *tzname[];
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* defined(_POSIX_C_SOURCE) || defined(__DOXYGEN__) */
+
+#endif /* ZEPHYR_INCLUDE_ZEPHYR_POSIX_POSIX_TIME_H_ */
diff --git a/include/zephyr/posix/pthread.h b/include/zephyr/posix/pthread.h
index 685a8d9a9316e..8b9b03e490c54 100644
--- a/include/zephyr/posix/pthread.h
+++ b/include/zephyr/posix/pthread.h
@@ -9,9 +9,9 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <time.h>
 
 #include <zephyr/kernel.h>
-#include <zephyr/posix/time.h>
 #include <zephyr/posix/unistd.h>
 #include <zephyr/posix/sched.h>
 
diff --git a/include/zephyr/posix/semaphore.h b/include/zephyr/posix/semaphore.h
index e3f6014cfec45..943df122cff59 100644
--- a/include/zephyr/posix/semaphore.h
+++ b/include/zephyr/posix/semaphore.h
@@ -6,7 +6,8 @@
 #ifndef ZEPHYR_INCLUDE_POSIX_SEMAPHORE_H_
 #define ZEPHYR_INCLUDE_POSIX_SEMAPHORE_H_
 
-#include <zephyr/posix/time.h>
+#include <time.h>
+
 #include <zephyr/posix/posix_types.h>
 
 #ifdef __cplusplus
diff --git a/include/zephyr/posix/signal.h b/include/zephyr/posix/signal.h
index 7513bfd104753..45dfb0caee4f2 100644
--- a/include/zephyr/posix/signal.h
+++ b/include/zephyr/posix/signal.h
@@ -6,6 +6,8 @@
 #ifndef ZEPHYR_INCLUDE_POSIX_SIGNAL_H_
 #define ZEPHYR_INCLUDE_POSIX_SIGNAL_H_
 
+#include <time.h>
+
 /* include posix_types.h before posix_features.h (here) to avoid build errors against newlib */
 #include <zephyr/posix/posix_types.h>
 #include "posix_features.h"
diff --git a/include/zephyr/posix/time.h b/include/zephyr/posix/time.h
deleted file mode 100644
index df2980601722e..0000000000000
--- a/include/zephyr/posix/time.h
+++ /dev/null
@@ -1,114 +0,0 @@
-/*
- * Copyright (c) 2018 Intel Corporation
- *
- * SPDX-License-Identifier: Apache-2.0
- */
-#ifndef ZEPHYR_INCLUDE_POSIX_TIME_H_
-#define ZEPHYR_INCLUDE_POSIX_TIME_H_
-
-/* Read standard header.  This may find <posix/time.h> since they
- * refer to the same file when include/posix is in the search path.
- */
-#include <time.h>
-
-#ifdef CONFIG_NEWLIB_LIBC
-/* Kludge to support outdated newlib version as used in SDK 0.10 for Xtensa */
-#include <newlib.h>
-
-#ifdef __NEWLIB__
-/* Newever Newlib 3.x+ */
-#include <sys/timespec.h>
-#else /* __NEWLIB__ */
-/* Workaround for older Newlib 2.x, as used by Xtensa. It lacks sys/_timeval.h,
- * so mimic it here.
- */
-#include <sys/types.h>
-#ifndef __timespec_defined
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-struct timespec {
-	time_t tv_sec;
-	long tv_nsec;
-};
-
-struct itimerspec {
-	struct timespec it_interval;  /* Timer interval */
-	struct timespec it_value;     /* Timer expiration */
-};
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* __timespec_defined */
-#endif /* __NEWLIB__ */
-
-#else /* CONFIG_NEWLIB_LIBC */
-/* Not Newlib */
-# if defined(CONFIG_ARCH_POSIX) && defined(CONFIG_EXTERNAL_LIBC)
-#  include <bits/types/struct_timespec.h>
-#  include <bits/types/struct_itimerspec.h>
-# else
-#  include <sys/timespec.h>
-# endif
-#endif /* CONFIG_NEWLIB_LIBC */
-
-#include <zephyr/kernel.h>
-#include <errno.h>
-#include <zephyr/posix/posix_types.h>
-#include <zephyr/posix/signal.h>
-#include <zephyr/sys/clock.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#ifndef CLOCK_REALTIME
-#define CLOCK_REALTIME SYS_CLOCK_REALTIME
-#endif
-
-#ifndef CLOCK_PROCESS_CPUTIME_ID
-#define CLOCK_PROCESS_CPUTIME_ID 2
-#endif
-
-#ifndef CLOCK_THREAD_CPUTIME_ID
-#define CLOCK_THREAD_CPUTIME_ID 3
-#endif
-
-#ifndef CLOCK_MONOTONIC
-#define CLOCK_MONOTONIC SYS_CLOCK_MONOTONIC
-#endif
-
-#ifndef TIMER_ABSTIME
-#define TIMER_ABSTIME SYS_TIMER_ABSTIME
-#endif
-
-int clock_gettime(clockid_t clock_id, struct timespec *ts);
-int clock_getres(clockid_t clock_id, struct timespec *ts);
-int clock_settime(clockid_t clock_id, const struct timespec *ts);
-int clock_getcpuclockid(pid_t pid, clockid_t *clock_id);
-/* Timer APIs */
-int timer_create(clockid_t clockId, struct sigevent *evp, timer_t *timerid);
-int timer_delete(timer_t timerid);
-struct itimerspec;
-int timer_gettime(timer_t timerid, struct itimerspec *its);
-int timer_settime(timer_t timerid, int flags, const struct itimerspec *value,
-		  struct itimerspec *ovalue);
-int timer_getoverrun(timer_t timerid);
-int nanosleep(const struct timespec *rqtp, struct timespec *rmtp);
-int clock_nanosleep(clockid_t clock_id, int flags,
-		    const struct timespec *rqtp, struct timespec *rmtp);
-
-#ifdef __cplusplus
-}
-#endif
-
-#else /* ZEPHYR_INCLUDE_POSIX_TIME_H_ */
-/* Read the toolchain header when <posix/time.h> finds itself on the
- * first attempt.
- */
-#include_next <time.h>
-#endif /* ZEPHYR_INCLUDE_POSIX_TIME_H_ */
diff --git a/include/zephyr/posix/unistd.h b/include/zephyr/posix/unistd.h
index 10d44bfd4a8d2..89f698159e1b4 100644
--- a/include/zephyr/posix/unistd.h
+++ b/include/zephyr/posix/unistd.h
@@ -6,6 +6,8 @@
 #ifndef ZEPHYR_INCLUDE_POSIX_UNISTD_H_
 #define ZEPHYR_INCLUDE_POSIX_UNISTD_H_
 
+#include <time.h>
+
 #include <zephyr/posix/posix_types.h>
 
 #ifdef CONFIG_POSIX_API
diff --git a/lib/libc/arcmwdt/include/limits.h b/lib/libc/arcmwdt/include/limits.h
index 96982ad6e4146..2e9a4d3fb4c68 100644
--- a/lib/libc/arcmwdt/include/limits.h
+++ b/lib/libc/arcmwdt/include/limits.h
@@ -8,23 +8,10 @@
 #define LIB_LIBC_ARCMWDT_INCLUDE_LIMITS_H_
 
 #include_next <limits.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#if defined(_POSIX_C_SOURCE) || defined(__DOXYGEN__)
-
 #include <zephyr/posix/posix_limits.h>
 
-#else
-
+#ifndef PATH_MAX
 #define PATH_MAX 256
-
-#endif
-
-#ifdef __cplusplus
-}
 #endif
 
-#endif  /* ZEPHYR_LIB_LIBC_ARMSTDC_INCLUDE_LIMITS_H_ */
+#endif  /* LIB_LIBC_ARCMWDT_INCLUDE_LIMITS_H_ */
diff --git a/lib/libc/arcmwdt/include/time.h b/lib/libc/arcmwdt/include/time.h
index 245bd3a77d236..1d9ed0a7a9a05 100644
--- a/lib/libc/arcmwdt/include/time.h
+++ b/lib/libc/arcmwdt/include/time.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024 Synopsys
+ * Copyright The Zephyr Project Contributors
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -8,18 +8,6 @@
 #define LIB_LIBC_ARCMWDT_INCLUDE_TIME_H_
 
 #include_next <time.h>
+#include <zephyr/posix/posix_time.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-extern char *asctime_r(const struct tm *tp, char *buf);
-extern char *ctime_r(const time_t *clock, char *buf);
-extern struct tm *gmtime_r(const time_t *timep, struct tm *result);
-extern struct tm *localtime_r(const time_t *timer, struct tm *result);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* LIB_LIBC_ARCMWDT_INCLUDE_TIME_H_ */
+#endif  /* LIB_LIBC_ARCMWDT_INCLUDE_TIME_H_ */
diff --git a/lib/libc/armstdc/include/limits.h b/lib/libc/armstdc/include/limits.h
index 13206aa68b566..54dabd8fdaa4a 100644
--- a/lib/libc/armstdc/include/limits.h
+++ b/lib/libc/armstdc/include/limits.h
@@ -8,23 +8,10 @@
 #define ZEPHYR_LIB_LIBC_ARMSTDC_INCLUDE_LIMITS_H_
 
 #include_next <limits.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#if defined(_POSIX_C_SOURCE) || defined(__DOXYGEN__)
-
 #include <zephyr/posix/posix_limits.h>
 
-#else
-
+#ifndef PATH_MAX
 #define PATH_MAX 256
-
-#endif
-
-#ifdef __cplusplus
-}
 #endif
 
 #endif  /* ZEPHYR_LIB_LIBC_ARMSTDC_INCLUDE_LIMITS_H_ */
diff --git a/lib/libc/armstdc/include/time.h b/lib/libc/armstdc/include/time.h
new file mode 100644
index 0000000000000..1432916b21188
--- /dev/null
+++ b/lib/libc/armstdc/include/time.h
@@ -0,0 +1,13 @@
+/*
+ * Copyright The Zephyr Project Contributors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_LIB_LIBC_ARMSTDC_INCLUDE_TIME_H_
+#define ZEPHYR_LIB_LIBC_ARMSTDC_INCLUDE_TIME_H_
+
+#include_next <time.h>
+#include <zephyr/posix/posix_time.h>
+
+#endif  /* ZEPHYR_LIB_LIBC_ARMSTDC_INCLUDE_TIME_H_ */
diff --git a/lib/libc/iar/include/limits.h b/lib/libc/iar/include/limits.h
index 6db549c355e92..010f0509649e7 100644
--- a/lib/libc/iar/include/limits.h
+++ b/lib/libc/iar/include/limits.h
@@ -8,23 +8,10 @@
 #define ZEPHYR_LIB_LIBC_IAR_INCLUDE_LIMITS_H_
 
 #include_next <limits.h>
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#if defined(_POSIX_C_SOURCE) || defined(__DOXYGEN__)
-
 #include <zephyr/posix/posix_limits.h>
 
-#else
-
+#ifndef PATH_MAX
 #define PATH_MAX 256
-
-#endif
-
-#ifdef __cplusplus
-}
 #endif
 
 #endif /* ZEPHYR_LIB_LIBC_IAR_INCLUDE_LIMITS_H_ */
diff --git a/lib/libc/iar/include/time.h b/lib/libc/iar/include/time.h
index b095987857418..2d4d2d9007578 100644
--- a/lib/libc/iar/include/time.h
+++ b/lib/libc/iar/include/time.h
@@ -1,31 +1,14 @@
 /*
- * Copyright (c) 2025 IAR Systems AB
+ * Copyright The Zephyr Project Contributors
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
-/**
- * @file
- * @brief Declares additional time related functions based on POSIX
- */
-
 #ifndef ZEPHYR_LIB_LIBC_IAR_INCLUDE_TIME_H_
 #define ZEPHYR_LIB_LIBC_IAR_INCLUDE_TIME_H_
 
 #include <zephyr/toolchain.h>
 #include_next <time.h>
+#include <zephyr/posix/posix_time.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-char      *asctime_r(const struct tm *ZRESTRICT tp, char *ZRESTRICT buf);
-char      *ctime_r(const time_t *clock, char *buf);
-struct tm *gmtime_r(const time_t *ZRESTRICT timep, struct tm *ZRESTRICT result);
-struct tm *localtime_r(const time_t *ZRESTRICT timer, struct tm *ZRESTRICT result);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* ZEPHYR_LIB_LIBC_IAR_INCLUDE_TIME_H_ */
+#endif  /* ZEPHYR_LIB_LIBC_IAR_INCLUDE_TIME_H_ */
diff --git a/lib/libc/minimal/include/time.h b/lib/libc/minimal/include/time.h
index 62ec45b03a171..3e795f0db4817 100644
--- a/lib/libc/minimal/include/time.h
+++ b/lib/libc/minimal/include/time.h
@@ -58,12 +58,12 @@ struct tm *gmtime_r(const time_t *ZRESTRICT timep,
 char *asctime(const struct tm *timeptr);
 struct tm *localtime(const time_t *timer);
 char *ctime(const time_t *clock);
-char *asctime_r(const struct tm *ZRESTRICT tp, char *ZRESTRICT buf);
-char *ctime_r(const time_t *clock, char *buf);
 struct tm *localtime_r(const time_t *ZRESTRICT timer, struct tm *ZRESTRICT result);
 
 time_t time(time_t *tloc);
 
+#include <zephyr/posix/posix_time.h>
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/libc/newlib/include/limits.h b/lib/libc/newlib/include/limits.h
new file mode 100644
index 0000000000000..81f9bbd406611
--- /dev/null
+++ b/lib/libc/newlib/include/limits.h
@@ -0,0 +1,13 @@
+/*
+ * Copyright The Zephyr Project Contributors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_LIB_LIBC_NEWLIB_INCLUDE_LIMITS_H_
+#define ZEPHYR_LIB_LIBC_NEWLIB_INCLUDE_LIMITS_H_
+
+#include_next <limits.h>
+#include <zephyr/posix/posix_limits.h>
+
+#endif /* ZEPHYR_LIB_LIBC_NEWLIB_INCLUDE_LIMITS_H_ */
diff --git a/lib/libc/picolibc/CMakeLists.txt b/lib/libc/picolibc/CMakeLists.txt
index 752379dd76d44..280a16a89454e 100644
--- a/lib/libc/picolibc/CMakeLists.txt
+++ b/lib/libc/picolibc/CMakeLists.txt
@@ -10,6 +10,7 @@ zephyr_library_sources(
   locks.c
   stdio.c
   )
+zephyr_include_directories(include)
 
 zephyr_library_compile_options($<TARGET_PROPERTY:compiler,prohibit_lto>)
 
diff --git a/lib/libc/picolibc/include/time.h b/lib/libc/picolibc/include/time.h
new file mode 100644
index 0000000000000..47113c10d81af
--- /dev/null
+++ b/lib/libc/picolibc/include/time.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright The Zephyr Project Contributors
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_LIB_LIBC_ARMSTDC_INCLUDE_TIME_H_
+#define ZEPHYR_LIB_LIBC_ARMSTDC_INCLUDE_TIME_H_
+
+
+#if defined(_POSIX_C_SOURCE) || defined(__DOXYGEN__)
+
+/* temporary workaround for https://github.com/picolibc/picolibc/pull/1079 */
+#include <sys/_types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef _PID_T_DECLARED
+typedef __pid_t pid_t;
+#define _PID_T_DECLARED
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* defined(_POSIX_C_SOURCE) || defined(__DOXYGEN__) */
+
+#include_next <time.h>
+
+#endif  /* ZEPHYR_LIB_LIBC_ARMSTDC_INCLUDE_TIME_H_ */
diff --git a/lib/posix/CMakeLists.txt b/lib/posix/CMakeLists.txt
index d62108b66f007..9a40cad191b26 100644
--- a/lib/posix/CMakeLists.txt
+++ b/lib/posix/CMakeLists.txt
@@ -1,4 +1,9 @@
 # SPDX-License-Identifier: Apache-2.0
 
-add_subdirectory(options)
+# zephyr-keep-sorted-start
+add_subdirectory_ifdef(CONFIG_EVENTFD eventfd)
+add_subdirectory_ifdef(CONFIG_POSIX_C_LANG_SUPPORT_R c_lang_support_r)
+add_subdirectory_ifdef(CONFIG_POSIX_C_LIB_EXT c_lib_ext)
 add_subdirectory_ifdef(CONFIG_POSIX_SHELL shell)
+add_subdirectory_ifdef(CONFIG_POSIX_SYSTEM_INTERFACES options)
+# zephyr-keep-sorted-stop
diff --git a/lib/posix/Kconfig b/lib/posix/Kconfig
index 534baf08cd240..4b93901ae17a5 100644
--- a/lib/posix/Kconfig
+++ b/lib/posix/Kconfig
@@ -1,10 +1,45 @@
 # Copyright (c) 2024 Meta
+# Copyright (c) 2025 Tenstorrent AI ULC
 #
 # SPDX-License-Identifier: Apache-2.0
 
 menu "POSIX API Support"
 
+# POSIX Subprofile Definitions
+rsource "Kconfig.profile"
+
+# Toolchain hooks for external implementations
+rsource "Kconfig.toolchain"
+
+# POSIX C Library Extensions
+# This menu is for POSIX Option Groups that do not require OS support.
+menu "POSIX C Library Extensions"
+rsource "c_lang_support_r/Kconfig"
+rsource "c_lib_ext/Kconfig"
+endmenu
+
+# POSIX System Interfaces
+menuconfig POSIX_SYSTEM_INTERFACES
+	bool "POSIX System Interfaces"
+	depends on !NATIVE_APPLICATION
+	select NATIVE_LIBC_INCOMPATIBLE
+	help
+	  Select 'y' here to support POSIX System Interfaces within Zephyr.
+
+	  Options in this menu are organized by POSIX subprofiling Option Group.
+
+	  For more information, see
+	  https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_subprofiles.html
+
+
+if POSIX_SYSTEM_INTERFACES
 rsource "options/Kconfig"
+
+# POSIX Shell utilities
 rsource "shell/Kconfig"
+endif
+
+endmenu
 
-endmenu # "POSIX API Support"
+# Eventfd Support (not officially POSIX)
+rsource "eventfd/Kconfig"
diff --git a/lib/posix/options/Kconfig.profile b/lib/posix/Kconfig.profile
similarity index 78%
rename from lib/posix/options/Kconfig.profile
rename to lib/posix/Kconfig.profile
index 99dc78c20ea24..eed95528f5e6a 100644
--- a/lib/posix/options/Kconfig.profile
+++ b/lib/posix/Kconfig.profile
@@ -2,7 +2,7 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-config POSIX_SYSTEM_HEADERS
+config POSIX_SYSTEM_INTERFACES
 	bool
 	select NATIVE_LIBC_INCOMPATIBLE
 	help
@@ -10,8 +10,7 @@ config POSIX_SYSTEM_HEADERS
 
 config POSIX_API
 	bool "POSIX APIs"
-	select NATIVE_LIBC_INCOMPATIBLE
-	select POSIX_SYSTEM_HEADERS
+	select POSIX_SYSTEM_INTERFACES
 	select POSIX_BASE_DEFINITIONS # clock_gettime(), pthread_create(), sem_get(), etc
 	select POSIX_AEP_REALTIME_MINIMAL # CLOCK_MONOTONIC, pthread_attr_setstack(), etc
 	select POSIX_NETWORKING if NETWORKING # inet_ntoa(), socket(), etc
@@ -27,7 +26,7 @@ config POSIX_API
 
 choice POSIX_AEP_CHOICE
 	prompt "POSIX Subprofile"
-	default POSIX_AEP_CHOICE_NONE
+	default POSIX_AEP_CHOICE_ZEPHYR
 	help
 	  This choice is intended to help users select the correct POSIX profile for their
 	  application. Choices are based on IEEE 1003.13-2003 (now inactive / reserved) and
@@ -38,13 +37,35 @@ choice POSIX_AEP_CHOICE
 	  https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_subprofiles.html
 
 config POSIX_AEP_CHOICE_NONE
-	bool "No pre-defined POSIX subprofile"
+	bool "No POSIX subprofile"
+	help
+	  No POSIX subprofile is selected.
+
+config POSIX_AEP_CHOICE_ZEPHYR
+	bool "Minimal Zephyr System Profile"
+	select POSIX_C_LIB_EXT
+	select POSIX_C_LANG_SUPPORT_R
 	help
-	  No pre-defined POSIX profile is selected.
+	  Zephyr expects certain POSIX functions to be available throughout the build environment,
+	  such as gmtime_r(), strnlen(), strtok_r(), and possibly others.
+
+	  These functions are divided into two standalone Option Groups that may be enabled
+	  independently of the remainder of the POSIX API implementation; namely POSIX_C_LIB_EXT and
+	  POSIX_C_LANG_SUPPORT_R. If not referenced by the Zephyr kernel or application, there are no
+	  resource implications for enabling these option groups.
+
+	  Unlike pre-defined, standard POSIX subprofiles, this subprofile is custom to Zephyr and
+	  therefore does not need to include the base definitions or system interfaces that would
+	  otherwise be required for a conformant POSIX system or subprofile. This system profile
+	  does not itself meet the requirements for POSIX implementation conformance.
+
+	  For more information, see
+	  https://docs.zephyrproject.org/latest/contribute/coding_guidelines/index.html
+	  https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_subprofiles.html
 
 config POSIX_AEP_CHOICE_BASE
-	bool "Base definitions (system interfaces)"
-	select NATIVE_LIBC_INCOMPATIBLE
+	bool "Minimal POSIX System Profile"
+	select POSIX_SYSTEM_INTERFACES
 	select POSIX_BASE_DEFINITIONS
 	help
 	  Only enable the base definitions required for all POSIX systems.
@@ -54,7 +75,7 @@ config POSIX_AEP_CHOICE_BASE
 
 config POSIX_AEP_CHOICE_PSE51
 	bool "Minimal Realtime System Profile (PSE51)"
-	select NATIVE_LIBC_INCOMPATIBLE
+	select POSIX_SYSTEM_INTERFACES
 	select POSIX_BASE_DEFINITIONS
 	select POSIX_AEP_REALTIME_MINIMAL
 	help
@@ -67,7 +88,7 @@ config POSIX_AEP_CHOICE_PSE51
 
 config POSIX_AEP_CHOICE_PSE52
 	bool "Realtime Controller System Profile (PSE52)"
-	select NATIVE_LIBC_INCOMPATIBLE
+	select POSIX_SYSTEM_INTERFACES
 	select POSIX_BASE_DEFINITIONS
 	select POSIX_AEP_REALTIME_MINIMAL
 	select POSIX_AEP_REALTIME_CONTROLLER
@@ -81,7 +102,7 @@ config POSIX_AEP_CHOICE_PSE52
 
 config POSIX_AEP_CHOICE_PSE53
 	bool "Dedicated Realtime System Profile (PSE53)"
-	select NATIVE_LIBC_INCOMPATIBLE
+	select POSIX_SYSTEM_INTERFACES
 	select POSIX_BASE_DEFINITIONS
 	select POSIX_AEP_REALTIME_MINIMAL
 	select POSIX_AEP_REALTIME_CONTROLLER
@@ -98,10 +119,11 @@ config POSIX_AEP_CHOICE_PSE53
 
 endchoice # POSIX_AEP_CHOICE
 
-# Base Definitions (System Interfaces)
+if POSIX_SYSTEM_INTERFACES
+
+# Mandatory POSIX System Interfaces (base profile)
 config POSIX_BASE_DEFINITIONS
 	bool
-	select POSIX_SYSTEM_HEADERS
 	select POSIX_ASYNCHRONOUS_IO
 	select POSIX_BARRIERS
 	select POSIX_CLOCK_SELECTION
@@ -187,3 +209,5 @@ config POSIX_AEP_REALTIME_DEDICATED
 
 	  For more information, please see
 	  https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_subprofiles.html
+
+endif # POSIX_SYSTEM_INTERFACE
diff --git a/lib/posix/options/Kconfig.toolchain b/lib/posix/Kconfig.toolchain
similarity index 100%
rename from lib/posix/options/Kconfig.toolchain
rename to lib/posix/Kconfig.toolchain
diff --git a/lib/posix/c_lang_support_r/CMakeLists.txt b/lib/posix/c_lang_support_r/CMakeLists.txt
new file mode 100644
index 0000000000000..db1e5c8d3a917
--- /dev/null
+++ b/lib/posix/c_lang_support_r/CMakeLists.txt
@@ -0,0 +1,8 @@
+# Copyright The Zephyr Project Contributors
+# SPDX-License-Identifier: Apache-2.0
+
+set(POSIX_VERSION 200809L)
+
+if (CONFIG_POSIX_C_LANG_SUPPORT_R)
+  zephyr_compile_definitions(-D_POSIX_THREAD_SAFE_FUNCTIONS=${POSIX_VERSION})
+endif()
diff --git a/lib/posix/options/Kconfig.c_lang_r b/lib/posix/c_lang_support_r/Kconfig
similarity index 100%
rename from lib/posix/options/Kconfig.c_lang_r
rename to lib/posix/c_lang_support_r/Kconfig
diff --git a/lib/posix/c_lib_ext/CMakeLists.txt b/lib/posix/c_lib_ext/CMakeLists.txt
new file mode 100644
index 0000000000000..a4c3e09d839f2
--- /dev/null
+++ b/lib/posix/c_lib_ext/CMakeLists.txt
@@ -0,0 +1,17 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_include_directories(getopt)
+
+if (CONFIG_TC_PROVIDES_POSIX_C_LIB_EXT)
+  return()
+endif()
+
+zephyr_library()
+zephyr_library_sources(
+  fnmatch.c
+  getentropy.c
+  getopt/getopt.c
+  getopt/getopt_common.c
+)
+
+zephyr_library_sources_ifdef(CONFIG_GETOPT_LONG getopt/getopt_long.c)
diff --git a/lib/posix/options/Kconfig.c_lib_ext b/lib/posix/c_lib_ext/Kconfig
similarity index 100%
rename from lib/posix/options/Kconfig.c_lib_ext
rename to lib/posix/c_lib_ext/Kconfig
diff --git a/lib/posix/options/fnmatch.c b/lib/posix/c_lib_ext/fnmatch.c
similarity index 100%
rename from lib/posix/options/fnmatch.c
rename to lib/posix/c_lib_ext/fnmatch.c
diff --git a/lib/posix/options/getentropy.c b/lib/posix/c_lib_ext/getentropy.c
similarity index 100%
rename from lib/posix/options/getentropy.c
rename to lib/posix/c_lib_ext/getentropy.c
diff --git a/lib/posix/options/getopt/README b/lib/posix/c_lib_ext/getopt/README
similarity index 100%
rename from lib/posix/options/getopt/README
rename to lib/posix/c_lib_ext/getopt/README
diff --git a/lib/posix/options/getopt/getopt.c b/lib/posix/c_lib_ext/getopt/getopt.c
similarity index 100%
rename from lib/posix/options/getopt/getopt.c
rename to lib/posix/c_lib_ext/getopt/getopt.c
diff --git a/lib/posix/options/getopt/getopt.h b/lib/posix/c_lib_ext/getopt/getopt.h
similarity index 100%
rename from lib/posix/options/getopt/getopt.h
rename to lib/posix/c_lib_ext/getopt/getopt.h
diff --git a/lib/posix/options/getopt/getopt_common.c b/lib/posix/c_lib_ext/getopt/getopt_common.c
similarity index 100%
rename from lib/posix/options/getopt/getopt_common.c
rename to lib/posix/c_lib_ext/getopt/getopt_common.c
diff --git a/lib/posix/options/getopt/getopt_common.h b/lib/posix/c_lib_ext/getopt/getopt_common.h
similarity index 100%
rename from lib/posix/options/getopt/getopt_common.h
rename to lib/posix/c_lib_ext/getopt/getopt_common.h
diff --git a/lib/posix/options/getopt/getopt_long.c b/lib/posix/c_lib_ext/getopt/getopt_long.c
similarity index 100%
rename from lib/posix/options/getopt/getopt_long.c
rename to lib/posix/c_lib_ext/getopt/getopt_long.c
diff --git a/lib/posix/eventfd/CMakeLists.txt b/lib/posix/eventfd/CMakeLists.txt
new file mode 100644
index 0000000000000..2736572dd0061
--- /dev/null
+++ b/lib/posix/eventfd/CMakeLists.txt
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+zephyr_library_sources(eventfd.c)
diff --git a/lib/posix/options/Kconfig.compat b/lib/posix/eventfd/Kconfig
similarity index 87%
rename from lib/posix/options/Kconfig.compat
rename to lib/posix/eventfd/Kconfig
index e15cc869a7be6..019daef4a3524 100644
--- a/lib/posix/options/Kconfig.compat
+++ b/lib/posix/eventfd/Kconfig
@@ -3,8 +3,6 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-menu "Miscellaneous POSIX-related options"
-
 config EVENTFD
 	bool "Support for eventfd"
 	select ZVFS
@@ -13,5 +11,3 @@ config EVENTFD
 	  Enable support for event file descriptors, eventfd. An eventfd can
 	  be used as an event wait/notify mechanism together with POSIX calls
 	  like read, write and poll.
-
-endmenu
diff --git a/lib/posix/options/eventfd.c b/lib/posix/eventfd/eventfd.c
similarity index 100%
rename from lib/posix/options/eventfd.c
rename to lib/posix/eventfd/eventfd.c
diff --git a/lib/posix/options/CMakeLists.txt b/lib/posix/options/CMakeLists.txt
index 5ef2032e5a91c..ac11617c28b84 100644
--- a/lib/posix/options/CMakeLists.txt
+++ b/lib/posix/options/CMakeLists.txt
@@ -1,12 +1,15 @@
 # SPDX-License-Identifier: Apache-2.0
 
+set(POSIX_VERSION 200809L)
 set(GEN_DIR ${ZEPHYR_BINARY_DIR}/include/generated)
 
+zephyr_compile_definitions(-D_POSIX_C_SOURCE=${POSIX_VERSION})
+
 zephyr_syscall_header_ifdef(CONFIG_POSIX_CLOCK_SELECTION posix_clock.h)
 zephyr_syscall_header_ifdef(CONFIG_POSIX_TIMERS posix_clock.h)
 zephyr_syscall_header_ifdef(CONFIG_XSI_SINGLE_PROCESS posix_clock.h)
 
-if(CONFIG_POSIX_SYSTEM_HEADERS)
+if(CONFIG_POSIX_SYSTEM_INTERFACES)
   zephyr_include_directories(${ZEPHYR_BASE}/include/zephyr/posix)
 endif()
 
@@ -27,8 +30,8 @@ if (NOT CONFIG_TC_PROVIDES_POSIX_SIGNALS)
 endif()
 
 if(CONFIG_POSIX_API OR CONFIG_POSIX_THREADS OR CONFIG_POSIX_TIMERS OR
-  CONFIG_POSIX_MESSAGE_PASSING OR CONFIG_POSIX_FILE_SYSTEM OR CONFIG_EVENTFD OR
-  CONFIG_POSIX_C_LIB_EXT OR CONFIG_POSIX_SINGLE_PROCESS)
+  CONFIG_POSIX_MESSAGE_PASSING OR CONFIG_POSIX_FILE_SYSTEM OR
+  CONFIG_POSIX_SINGLE_PROCESS)
   # This is a temporary workaround so that Newlib declares the appropriate
   # types for us. POSIX features to be formalized as part of #51211
   zephyr_compile_options($<$<COMPILE_LANGUAGE:C>:-D_POSIX_THREADS>)
@@ -36,7 +39,6 @@ if(CONFIG_POSIX_API OR CONFIG_POSIX_THREADS OR CONFIG_POSIX_TIMERS OR
 endif()
 
 zephyr_library()
-zephyr_library_sources_ifdef(CONFIG_EVENTFD eventfd.c)
 
 if (NOT CONFIG_TC_PROVIDES_POSIX_ASYNCHRONOUS_IO)
   zephyr_library_sources_ifdef(CONFIG_POSIX_ASYNCHRONOUS_IO aio.c)
@@ -50,15 +52,6 @@ if (NOT CONFIG_TC_PROVIDES_POSIX_CLOCK_SELECTION)
   zephyr_library_sources_ifdef(CONFIG_POSIX_CLOCK_SELECTION clock_selection.c)
 endif()
 
-if (NOT CONFIG_TC_PROVIDES_POSIX_C_LIB_EXT)
-  zephyr_library_sources_ifdef(CONFIG_POSIX_C_LIB_EXT
-    fnmatch.c
-    getentropy.c
-    getopt/getopt.c
-    getopt/getopt_common.c
-  )
-endif()
-
 if (NOT CONFIG_TC_PROVIDES_POSIX_DEVICE_IO)
   zephyr_library_sources_ifdef(CONFIG_POSIX_DEVICE_IO
     # perror should be moved to the common libc
@@ -80,6 +73,9 @@ endif()
 if (NOT CONFIG_TC_PROVIDES_POSIX_FILE_SYSTEM_R)
   zephyr_library_sources_ifdef(CONFIG_POSIX_FILE_SYSTEM_R file_system_r.c)
 endif()
+if (CONFIG_POSIX_FILE_SYSTEM_R)
+  zephyr_compile_definitions(-D_POSIX_THREAD_SAFE_FUNCTIONS=${POSIX_VERSION})
+endif()
 
 if (NOT CONFIG_TC_PROVIDES_POSIX_MEMORY_PROTECTION)
 zephyr_library_sources_ifdef(CONFIG_POSIX_MEMORY_PROTECTION mprotect.c)
@@ -125,6 +121,15 @@ if (NOT CONFIG_TC_PROVIDES_POSIX_TIMERS)
     timespec_to_timeout.c
   )
 endif()
+if (CONFIG_POSIX_TIMERS)
+  zephyr_compile_definitions(-D_POSIX_TIMERS=${POSIX_VERSION})
+  # FIXME: Until we have CONFIG_XSI_ADVANCED_REALTIME define _POSIX_CPUTIME and
+  # _POSIX_MONOTONIC_CLOCK with _POSIX_TIMERS.
+  # For more information on the Advanced Realtime Option Group, please see
+  # https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap02.html
+  zephyr_compile_definitions(-D_POSIX_CPUTIME=${POSIX_VERSION})
+  zephyr_compile_definitions(-D_POSIX_MONOTONIC_CLOCK=${POSIX_VERSION})
+endif()
 
 if (NOT CONFIG_TC_PROVIDES_POSIX_READER_WRITER_LOCKS)
   # Note: the Option is _POSIX_READER_WRITER_LOCKS, while the Option Group is POSIX_RW_LOCKS.
@@ -171,13 +176,6 @@ if (NOT CONFIG_TC_PROVIDES_XSI_SYSTEM_LOGGING)
   zephyr_library_sources_ifdef(CONFIG_XSI_SYSTEM_LOGGING syslog.c)
 endif()
 
-zephyr_library_sources_ifdef(CONFIG_GETOPT_LONG
-  getopt/getopt_long.c
-)
-zephyr_include_directories_ifdef(CONFIG_POSIX_C_LIB_EXT
-  getopt/
-)
-
 zephyr_library_include_directories(
   ${ZEPHYR_BASE}/kernel/include
   ${ARCH_DIR}/${ARCH}/include
diff --git a/lib/posix/options/Kconfig b/lib/posix/options/Kconfig
index 6c2b129170e30..3f072a293f6be 100644
--- a/lib/posix/options/Kconfig
+++ b/lib/posix/options/Kconfig
@@ -4,14 +4,9 @@
 #
 # SPDX-License-Identifier: Apache-2.0
 
-menu "POSIX Options"
-
-rsource "Kconfig.profile"
-
+# zephyr-keep-sorted-start
 rsource "Kconfig.aio"
 rsource "Kconfig.barrier"
-rsource "Kconfig.c_lang_r"
-rsource "Kconfig.c_lib_ext"
 rsource "Kconfig.device_io"
 rsource "Kconfig.fd_mgmt"
 rsource "Kconfig.file_system_r"
@@ -29,19 +24,16 @@ rsource "Kconfig.signal"
 rsource "Kconfig.spinlock"
 rsource "Kconfig.sync_io"
 rsource "Kconfig.timer"
+# zephyr-keep-sorted-stop
 
 menu "X/Open system interfaces"
 
+# zephyr-keep-sorted-start
 rsource "Kconfig.xsi_realtime"
 rsource "Kconfig.xsi_single_process"
 rsource "Kconfig.xsi_streams"
 rsource "Kconfig.xsi_system_logging"
 rsource "Kconfig.xsi_threads_ext"
+# zephyr-keep-sorted-stop
 
 endmenu # "X/Open system interfaces"
-
-rsource "Kconfig.compat"
-
-rsource "Kconfig.toolchain"
-
-endmenu # "POSIX Options"
diff --git a/lib/posix/options/Kconfig.pthread b/lib/posix/options/Kconfig.pthread
index 438506fe2182f..37aab14d472bd 100644
--- a/lib/posix/options/Kconfig.pthread
+++ b/lib/posix/options/Kconfig.pthread
@@ -157,6 +157,10 @@ config POSIX_THREAD_PRIO_PROTECT
 	  For more information, please see
 	  https://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutexattr_getprotocol.html
 
+# FIXME: this is an option, not an option group, and probably should be removed.
+# Furthermore, it should also depend on POSIX_FILE_LOCKING and POSIX_SYSTEM_DATABASE_R rather
+# than select any other options. The feature test macro _POSIX_THREAD_SAFE_FUNCTIONS should be
+# enabled when dependencies are satisfied.
 config POSIX_THREAD_SAFE_FUNCTIONS
 	bool "POSIX thread-safe functions"
 	select POSIX_FILE_SYSTEM_R
diff --git a/lib/posix/options/clock.c b/lib/posix/options/clock.c
index 466974705ac3a..faa85cae775fc 100644
--- a/lib/posix/options/clock.c
+++ b/lib/posix/options/clock.c
@@ -10,7 +10,6 @@
 
 #include <zephyr/kernel.h>
 #include <zephyr/posix/sys/time.h>
-#include <zephyr/posix/time.h>
 #include <zephyr/posix/unistd.h>
 #include <zephyr/sys/clock.h>
 
diff --git a/lib/posix/options/clock_selection.c b/lib/posix/options/clock_selection.c
index 5717221b596ec..67e5a89eaccfe 100644
--- a/lib/posix/options/clock_selection.c
+++ b/lib/posix/options/clock_selection.c
@@ -12,7 +12,6 @@
 #include <time.h>
 #include <errno.h>
 
-#include <zephyr/posix/time.h>
 #include <zephyr/sys/clock.h>
 #include <zephyr/toolchain.h>
 
diff --git a/lib/posix/options/grp.c b/lib/posix/options/grp.c
index 32c840e10164f..af395c88fa00c 100644
--- a/lib/posix/options/grp.c
+++ b/lib/posix/options/grp.c
@@ -9,8 +9,6 @@
 #include <zephyr/sys/util.h>
 #include <zephyr/posix/grp.h>
 
-#ifdef CONFIG_POSIX_THREAD_SAFE_FUNCTIONS
-
 int getgrnam_r(const char *name, struct group *grp, char *buffer, size_t bufsize,
 	       struct group **result)
 {
@@ -33,5 +31,3 @@ int getgrgid_r(gid_t gid, struct group *grp, char *buffer, size_t bufsize, struc
 
 	return ENOSYS;
 }
-
-#endif /* CONFIG_POSIX_THREAD_SAFE_FUNCTIONS */
diff --git a/lib/posix/options/pwd.c b/lib/posix/options/pwd.c
index f806767f3df90..5cafbb0a3a94a 100644
--- a/lib/posix/options/pwd.c
+++ b/lib/posix/options/pwd.c
@@ -9,8 +9,6 @@
 #include <zephyr/sys/util.h>
 #include <zephyr/posix/pwd.h>
 
-#ifdef CONFIG_POSIX_THREAD_SAFE_FUNCTIONS
-
 int getpwnam_r(const char *nam, struct passwd *pwd, char *buffer, size_t bufsize,
 	       struct passwd **result)
 {
@@ -33,5 +31,3 @@ int getpwuid_r(uid_t uid, struct passwd *pwd, char *buffer, size_t bufsize, stru
 
 	return ENOSYS;
 }
-
-#endif /* CONFIG_POSIX_THREAD_SAFE_FUNCTIONS */
diff --git a/lib/posix/options/timer.c b/lib/posix/options/timer.c
index 257fdce59ef36..ae2a263ff64b1 100644
--- a/lib/posix/options/timer.c
+++ b/lib/posix/options/timer.c
@@ -11,12 +11,12 @@
 #include "posix_clock.h"
 
 #include <errno.h>
+#include <time.h>
 
 #include <zephyr/kernel.h>
 #include <zephyr/logging/log.h>
 #include <zephyr/posix/pthread.h>
 #include <zephyr/posix/signal.h>
-#include <zephyr/posix/time.h>
 
 #define ACTIVE 1
 #define NOT_ACTIVE 0
diff --git a/tests/lib/c_lib/thrd/src/thrd.h b/tests/lib/c_lib/thrd/src/thrd.h
index 103b30a4f5f63..35d71eb07ab86 100644
--- a/tests/lib/c_lib/thrd/src/thrd.h
+++ b/tests/lib/c_lib/thrd/src/thrd.h
@@ -8,8 +8,8 @@
 #define TESTS_LIB_CLIB_SRC_TEST_THRD_H_
 
 #include <stdint.h>
+#include <time.h>
 
-#include <zephyr/posix/time.h>
 #include <zephyr/sys_clock.h>
 #include <zephyr/sys/timeutil.h>
 
diff --git a/tests/posix/common/src/clock.c b/tests/posix/common/src/clock.c
index a1b1336d0ce27..2467ac4df4bb9 100644
--- a/tests/posix/common/src/clock.c
+++ b/tests/posix/common/src/clock.c
@@ -9,6 +9,7 @@
 
 #include <limits.h>
 #include <sys/time.h>
+#include <time.h>
 #include <unistd.h>
 
 #include <zephyr/ztest.h>
diff --git a/tests/posix/common/src/mutex.c b/tests/posix/common/src/mutex.c
index 40987d50297a0..20b992620eb8a 100644
--- a/tests/posix/common/src/mutex.c
+++ b/tests/posix/common/src/mutex.c
@@ -6,6 +6,7 @@
 
 #include <errno.h>
 #include <pthread.h>
+#include <time.h>
 
 #include <zephyr/sys/util.h>
 #include <zephyr/ztest.h>
@@ -182,7 +183,7 @@ static void *test_mutex_timedlock_fn(void *arg)
 	struct timespec time_point;
 	pthread_mutex_t *mtx = (pthread_mutex_t *)arg;
 
-	zassume_ok(clock_gettime(CLOCK_MONOTONIC, &time_point));
+	zassume_ok(clock_gettime(CLOCK_REALTIME, &time_point));
 	timespec_add_ms(&time_point, TIMEDLOCK_TIMEOUT_MS);
 
 	return INT_TO_POINTER(pthread_mutex_timedlock(mtx, &time_point));
diff --git a/tests/posix/common/src/pthread.c b/tests/posix/common/src/pthread.c
index 035730ee4dc73..96a16f7ddb33b 100644
--- a/tests/posix/common/src/pthread.c
+++ b/tests/posix/common/src/pthread.c
@@ -6,6 +6,7 @@
 
 #include <pthread.h>
 #include <semaphore.h>
+#include <time.h>
 
 #include <zephyr/sys/util.h>
 #include <zephyr/ztest.h>
@@ -409,8 +410,8 @@ ZTEST(pthread, test_pthread_timedjoin)
 	};
 
 	/* setup timespecs when the thread is still running and when it is done */
-	clock_gettime(CLOCK_MONOTONIC, &not_done);
-	clock_gettime(CLOCK_MONOTONIC, &done);
+	clock_gettime(CLOCK_REALTIME, &not_done);
+	clock_gettime(CLOCK_REALTIME, &done);
 	not_done.tv_nsec += sleep_duration_ms / 2 * NSEC_PER_MSEC;
 	done.tv_nsec += sleep_duration_ms * 1.5 * NSEC_PER_MSEC;
 	while (not_done.tv_nsec >= NSEC_PER_SEC) {
diff --git a/tests/posix/semaphores/src/main.c b/tests/posix/semaphores/src/main.c
index 4ea118af926ce..c8b566349a644 100644
--- a/tests/posix/semaphores/src/main.c
+++ b/tests/posix/semaphores/src/main.c
@@ -9,6 +9,7 @@
 #include <fcntl.h>
 #include <pthread.h>
 #include <semaphore.h>
+#include <time.h>
 
 #include <zephyr/sys/timeutil.h>
 #include <zephyr/sys/util.h>
diff --git a/tests/posix/single_process/prj.conf b/tests/posix/single_process/prj.conf
index 7422432b9d0b8..ceec42c12c048 100644
--- a/tests/posix/single_process/prj.conf
+++ b/tests/posix/single_process/prj.conf
@@ -1,4 +1,5 @@
 CONFIG_ZTEST=y
+CONFIG_POSIX_SYSTEM_INTERFACES=y
 CONFIG_POSIX_SINGLE_PROCESS=y
 
 # Let's explicitly choose PICOLIBC, so it is used if supported even if it would not have been the
diff --git a/tests/posix/timers/src/timer.c b/tests/posix/timers/src/timer.c
index 1d4936d6a4be6..49e896f991e43 100644
--- a/tests/posix/timers/src/timer.c
+++ b/tests/posix/timers/src/timer.c
@@ -9,6 +9,7 @@
 
 #include <zephyr/ztest.h>
 #include <zephyr/logging/log.h>
+#include <zephyr/posix/signal.h>
 
 #define SECS_TO_SLEEP  2
 #define DURATION_SECS  1