diff --git a/compat/Makefile.am b/compat/Makefile.am
index f7875117d0c..1824c27e286 100644
--- a/compat/Makefile.am
+++ b/compat/Makefile.am
@@ -69,6 +69,8 @@ libcompatsquid_la_SOURCES = \
 	select.h \
 	shm.cc \
 	shm.h \
+	signal.cc \
+	signal.h \
 	socket.cc \
 	socket.h \
 	statvfs.cc \
diff --git a/compat/mswindows.cc b/compat/mswindows.cc
index 6ce80cd3797..50fda2413d8 100644
--- a/compat/mswindows.cc
+++ b/compat/mswindows.cc
@@ -61,52 +61,6 @@ chroot(const char *dirname)
         return GetLastError();
 }
 
-void
-GetProcessName(pid_t pid, char *ProcessName)
-{
-    strcpy(ProcessName, "unknown");
-#if defined(PSAPI_VERSION)
-    /* Get a handle to the process. */
-    HANDLE hProcess = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, pid);
-    /* Get the process name. */
-    if (hProcess) {
-        HMODULE hMod;
-        DWORD cbNeeded;
-
-        if (EnumProcessModules(hProcess, &hMod, sizeof(hMod), &cbNeeded))
-            GetModuleBaseName(hProcess, hMod, ProcessName, sizeof(ProcessName));
-        else {
-            CloseHandle(hProcess);
-            return;
-        }
-    } else
-        return;
-    CloseHandle(hProcess);
-#endif
-}
-
-int
-kill(pid_t pid, int sig)
-{
-    HANDLE hProcess;
-    char MyProcessName[MAX_PATH];
-    char ProcessNameToCheck[MAX_PATH];
-
-    if (sig == 0) {
-        if (!(hProcess = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, pid)))
-            return -1;
-        else {
-            CloseHandle(hProcess);
-            GetProcessName(getpid(), MyProcessName);
-            GetProcessName(pid, ProcessNameToCheck);
-            if (strcmp(MyProcessName, ProcessNameToCheck) == 0)
-                return 0;
-            return -1;
-        }
-    } else
-        return 0;
-}
-
 #if !HAVE_GETTIMEOFDAY
 int
 gettimeofday(struct timeval *pcur_time, void *tzp)
diff --git a/compat/os/mswindows.h b/compat/os/mswindows.h
index 96a0faa9ba9..3e29eef802e 100644
--- a/compat/os/mswindows.h
+++ b/compat/os/mswindows.h
@@ -220,14 +220,6 @@ setenv(const char * const name, const char * const value, const int overwrite)
 #define S_ISDIR(m) (((m) & _S_IFDIR) == _S_IFDIR)
 #endif
 
-#define SIGHUP  1   /* hangup */
-#define SIGKILL 9   /* kill (cannot be caught or ignored) */
-#define SIGBUS  10  /* bus error */
-#define SIGPIPE 13  /* write on a pipe with no one to read it */
-#define SIGCHLD 20  /* to parent on child stop or exit */
-#define SIGUSR1 30  /* user defined signal 1 */
-#define SIGUSR2 31  /* user defined signal 2 */
-
 #if defined(_MSC_VER)
 typedef int uid_t;
 typedef int gid_t;
@@ -534,7 +526,6 @@ struct rusage {
 #undef ACL
 
 SQUIDCEXTERN int chroot(const char *dirname);
-SQUIDCEXTERN int kill(pid_t, int);
 SQUIDCEXTERN struct passwd * getpwnam(char *unused);
 SQUIDCEXTERN struct group * getgrnam(char *unused);
 
diff --git a/compat/signal.cc b/compat/signal.cc
new file mode 100644
index 00000000000..ca86e12eed1
--- /dev/null
+++ b/compat/signal.cc
@@ -0,0 +1,82 @@
+/*
+ * Copyright (C) 1996-2025 The Squid Software Foundation and contributors
+ *
+ * Squid software is distributed under GPLv2+ license and includes
+ * contributions from numerous individuals and organizations.
+ * Please see the COPYING and CONTRIBUTORS files for details.
+ */
+
+#include "squid.h"
+#include "compat/signal.h"
+
+#if _SQUID_WINDOWS_ || _SQUID_MINGW_
+
+#ifdef HAVE_PSAPI_H
+#include <psapi.h>
+#endif
+
+static void
+GetProcessName(pid_t pid, char *ProcessName)
+{
+    strcpy(ProcessName, "unknown");
+
+    auto hProcess = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, pid);
+    if (!hProcess) // If we cannot open the process, we cannot get its name.
+        return;
+
+    /* Get the process name. */
+    HMODULE hMod;
+    DWORD cbNeeded;
+
+    if (EnumProcessModules(hProcess, &hMod, sizeof(hMod), &cbNeeded)) {
+        GetModuleBaseName(hProcess, hMod, ProcessName, sizeof(ProcessName));
+    }
+    CloseHandle(hProcess);
+}
+
+/// true if the given pid is the current process, false otherwise
+bool
+IsPidValid(pid_t pid)
+{
+    char MyProcessName[MAX_PATH];
+    GetProcessName(getpid(), MyProcessName);
+    char ProcessNameToCheck[MAX_PATH];
+    GetProcessName(pid, ProcessNameToCheck);
+    if (strcmp(MyProcessName, ProcessNameToCheck) == 0)
+        return true;
+    return false;
+}
+
+int
+xkill(pid_t pid, int sig)
+{
+    auto hProcess = OpenProcess(PROCESS_QUERY_INFORMATION | PROCESS_VM_READ, FALSE, pid);
+
+    if (!hProcess)
+        return -1;
+
+    switch (sig) {
+// Windows does not support sending generic POSIX signals.
+// TODO: implement a signal sending and handling mechanism
+// using Windows messages
+    case SIGKILL:
+        if (TerminateProcess(hProcess, 0)) {
+            CloseHandle(hProcess);
+            return 0;
+        }
+        break;
+    case 0:
+        CloseHandle(hProcess);
+        if (IsPidValid(pid))
+            return 0;
+        return -1;
+        break;
+    default:
+        // Unsupported signal
+        CloseHandle(hProcess);
+    }
+
+    return -1;
+}
+
+#endif /* _SQUID_WINDOWS_ || _SQUID_MINGW_ */
\ No newline at end of file
diff --git a/compat/signal.h b/compat/signal.h
new file mode 100644
index 00000000000..ed80ef58f9f
--- /dev/null
+++ b/compat/signal.h
@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 1996-2025 The Squid Software Foundation and contributors
+ *
+ * Squid software is distributed under GPLv2+ license and includes
+ * contributions from numerous individuals and organizations.
+ * Please see the COPYING and CONTRIBUTORS files for details.
+ */
+
+#ifndef SQUID_COMPAT_SIGNAL_H
+#define SQUID_COMPAT_SIGNAL_H
+
+#if !defined(SIGHUP)
+#define SIGHUP  1   /* hangup */
+#endif
+#if !defined(SIGKILL)
+#define SIGKILL 9   /* kill (cannot be caught or ignored) */
+#endif
+#if !defined(SIGBUS)
+#define SIGBUS  10  /* bus error */
+#endif
+#if !defined(SIGPIPE)
+#define SIGPIPE 13  /* write on a pipe with no one to read it */
+#endif
+#if !defined(SIGALRM)
+#define SIGALRM 14  /* real-time timer expired */
+#endif
+#if !defined(SIGCHLD)
+#define SIGCHLD 20  /* to parent on child stop or exit */
+#endif
+#if !defined(SIGUSR1)
+#define SIGUSR1 30  /* user defined signal 1 */
+#endif
+#if !defined(SIGUSR2)
+#define SIGUSR2 31  /* user defined signal 2 */
+#endif
+
+/// POSIX kill(2) equivalent
+int xkill(pid_t pid, int sig);
+
+/// true if pid can be sent a signal (no signal is sent)
+inline bool
+IsPidValid(pid_t pid);
+
+#if !defined(WIFEXITED)
+inline int
+WIFEXITED(int status) {
+    return (status & 0x7f) == 0;
+}
+#endif
+
+#if !defined(WEXITSTATUS)
+inline int
+WEXITSTATUS(int status) {
+    return (status & 0xff00) >> 8;
+}
+#endif
+
+#if !defined(WIFSIGNALED)
+inline int
+WIFSIGNALED(int status) {
+    return (status & 0x7f) != 0;
+}
+#endif
+
+#if !defined(WTERMSIG)
+inline int
+WTERMSIG(int status) {
+    return (status & 0x7f);
+}
+#endif
+
+#if !(_SQUID_WINDOWS_ || _SQUID_MINGW_)
+
+inline int xkill(pid_t pid, int sig)
+{
+    return kill(pid, sig);
+}
+
+inline bool
+IsPidValid(pid_t pid)
+{
+    return kill(pid, 0) == 0;
+}
+
+#endif /* !(_SQUID_WINDOWS_ || _SQUID_MINGW_) */
+
+#endif /* SQUID_COMPAT_SIGNAL_H */
diff --git a/src/Instance.cc b/src/Instance.cc
index e8d7dd52b80..d960150642b 100644
--- a/src/Instance.cc
+++ b/src/Instance.cc
@@ -8,6 +8,7 @@
 
 #include "squid.h"
 #include "base/File.h"
+#include "compat/signal.h"
 #include "debug/Messages.h"
 #include "fs_io.h"
 #include "Instance.h"
@@ -95,7 +96,7 @@ GetOtherPid(File &pidFile)
 static bool
 ProcessIsRunning(const pid_t pid)
 {
-    const auto result = kill(pid, 0);
+    const auto result = IsPidValid(pid);
     const auto savedErrno = errno;
     if (result != 0)
         debugs(50, 3, "kill(" << pid << ", 0) failed: " << xstrerr(savedErrno));
diff --git a/src/cache_cf.cc b/src/cache_cf.cc
index c0af0b6d14d..947a64a2e7b 100644
--- a/src/cache_cf.cc
+++ b/src/cache_cf.cc
@@ -29,6 +29,7 @@
 #include "CachePeer.h"
 #include "CachePeers.h"
 #include "compat/netdb.h"
+#include "compat/signal.h"
 #include "compat/socket.h"
 #include "ConfigOption.h"
 #include "ConfigParser.h"
diff --git a/src/ipc/Coordinator.cc b/src/ipc/Coordinator.cc
index 7f5aba55ae9..811e3ba28b4 100644
--- a/src/ipc/Coordinator.cc
+++ b/src/ipc/Coordinator.cc
@@ -14,6 +14,7 @@
 #include "CacheManager.h"
 #include "comm.h"
 #include "comm/Connection.h"
+#include "compat/signal.h"
 #include "compat/unistd.h"
 #include "ipc/Coordinator.h"
 #include "ipc/SharedListen.h"
@@ -289,7 +290,7 @@ void Ipc::Coordinator::broadcastSignal(int sig) const
     for (SCI iter = strands_.begin(); iter != strands_.end(); ++iter) {
         debugs(54, 5, "signal " << sig << " to kid" << iter->kidId <<
                ", PID=" << iter->pid);
-        kill(iter->pid, sig);
+        xkill(iter->pid, sig);
     }
 }
 
diff --git a/src/ipc/Kid.cc b/src/ipc/Kid.cc
index dd147e7ffd1..9ddf64cc484 100644
--- a/src/ipc/Kid.cc
+++ b/src/ipc/Kid.cc
@@ -9,6 +9,7 @@
 /* DEBUG: section 54    Interprocess Communication */
 
 #include "squid.h"
+#include "compat/signal.h"
 #include "globals.h"
 #include "ipc/Kid.h"
 #include "SquidConfig.h"
diff --git a/src/log/ModDaemon.cc b/src/log/ModDaemon.cc
index d0b77b3c95b..a5715d2f534 100644
--- a/src/log/ModDaemon.cc
+++ b/src/log/ModDaemon.cc
@@ -11,6 +11,7 @@
 #include "squid.h"
 #include "cbdata.h"
 #include "comm/Loops.h"
+#include "compat/signal.h"
 #include "fatal.h"
 #include "fde.h"
 #include "globals.h"
@@ -261,7 +262,7 @@ logfile_mod_daemon_close(Logfile * lf)
         comm_close(ll->rfd);
         comm_close(ll->wfd);
     }
-    kill(ll->pid, SIGTERM);
+    xkill(ll->pid, SIGTERM);
     eventDelete(logfileFlushEvent, lf);
     xfree(ll);
     lf->data = nullptr;
diff --git a/src/main.cc b/src/main.cc
index c18dde60d71..f2671f107b1 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -25,6 +25,7 @@
 #include "client_side.h"
 #include "comm.h"
 #include "CommandLine.h"
+#include "compat/signal.h"
 #include "compat/unistd.h"
 #include "ConfigParser.h"
 #include "CpuAffinity.h"
@@ -1666,7 +1667,7 @@ sendSignal(void)
     WIN32_sendSignal(opt_send_signal);
 #else
     const auto pid = Instance::Other();
-    if (kill(pid, opt_send_signal) &&
+    if (xkill(pid, opt_send_signal) &&
             /* ignore permissions if just running check */
             !(opt_send_signal == 0 && errno == EPERM)) {
         const auto savedErrno = errno;
diff --git a/src/mgr/BasicActions.cc b/src/mgr/BasicActions.cc
index 2471f7d68ed..8755b2afd3f 100644
--- a/src/mgr/BasicActions.cc
+++ b/src/mgr/BasicActions.cc
@@ -11,6 +11,7 @@
 #include "squid.h"
 #include "base/TextException.h"
 #include "CacheManager.h"
+#include "compat/signal.h"
 #include "mgr/ActionCreator.h"
 #include "mgr/ActionProfile.h"
 #include "mgr/BasicActions.h"
diff --git a/src/tools.cc b/src/tools.cc
index 5361b759a9c..69ab62ffef5 100644
--- a/src/tools.cc
+++ b/src/tools.cc
@@ -12,6 +12,7 @@
 #include "anyp/PortCfg.h"
 #include "base/Subscription.h"
 #include "client_side.h"
+#include "compat/signal.h"
 #include "compat/unistd.h"
 #include "fatal.h"
 #include "fde.h"
@@ -423,7 +424,7 @@ BroadcastSignalIfAny(int& sig)
             for (int i = TheKids.count() - 1; i >= 0; --i) {
                 const auto &kid = TheKids.get(i);
                 if (kid.running())
-                    kill(kid.getPid(), sig);
+                    xkill(kid.getPid(), sig);
             }
         }
         sig = -1;
diff --git a/src/windows_service.cc b/src/windows_service.cc
index 861b4b38f40..e4f2e4b77f2 100644
--- a/src/windows_service.cc
+++ b/src/windows_service.cc
@@ -9,6 +9,7 @@
 /* Inspired by previous work by Romeo Anghelache & Eric Stern. */
 
 #include "squid.h"
+#include "compat/signal.h"
 #include "debug/Stream.h"
 #include "globals.h"
 #include "protos.h"