diff --git a/ext/standard/basic_functions.c b/ext/standard/basic_functions.c
index 6e923d20ecbd..4f8161fd1f80 100644
--- a/ext/standard/basic_functions.c
+++ b/ext/standard/basic_functions.c
@@ -1113,18 +1113,56 @@ PHP_FUNCTION(flush)
 /* {{{ Delay for a given number of seconds */
 PHP_FUNCTION(sleep)
 {
-	zend_long num;
+	zval* num;
 
 	ZEND_PARSE_PARAMETERS_START(1, 1)
-		Z_PARAM_LONG(num)
+	Z_PARAM_NUMBER(num)
 	ZEND_PARSE_PARAMETERS_END();
-
-	if (num < 0) {
+	if (Z_TYPE_P(num) == IS_DOUBLE) {
+		const double seconds = Z_DVAL_P(num);
+		if (UNEXPECTED(seconds < 0)) {
+			zend_argument_value_error(1, "must be greater than or equal to 0");
+			RETURN_THROWS();
+		}
+#ifdef HAVE_NANOSLEEP
+		time_t seconds_long = (time_t)seconds;
+		zend_long fraction_nanoseconds = (zend_long)((seconds - seconds_long) * 1000000000);
+		if (fraction_nanoseconds > 999999999) {
+			// for this to happen, you have to request to sleep for longer than
+			// 0.999999999 seconds and yet less than 1 second..
+			// nanosleep() has a documented limit of 999999999 nanoseconds, so let's just round it up to 1 second.
+			// that means we'll be off by <=0.9 nanoseconds in this edge-case, probably close enough.
+			fraction_nanoseconds = 0;
+			seconds_long += 1;
+		}
+		struct timespec php_req, php_rem;
+		php_req.tv_sec = (time_t)seconds_long;
+		php_req.tv_nsec = fraction_nanoseconds;
+		const int result = nanosleep(&php_req, &php_rem);
+		if (UNEXPECTED(result == -1)) {
+			ZEND_ASSERT(errno != EINVAL); // this should be impossible, we carefully checked the input above
+			// it's probably EINTR
+			RETURN_DOUBLE(php_rem.tv_sec + (((double)php_rem.tv_nsec) / 1000000000.0));
+		}
+		RETURN_LONG(0);
+#elif defined(HAVE_USLEEP)
+		const unsigned int fraction_microseconds = (unsigned int)((seconds - (unsigned int)seconds) * 1000000);
+		if (fraction_microseconds > 0) {
+			usleep(fraction_microseconds);
+		}
+		RETURN_LONG(php_sleep((unsigned int)seconds));
+#else
+		// avoid -Werror=unreachable-code
+		RETURN_LONG(php_sleep((unsigned int)seconds));
+#endif
+	}
+	ZEND_ASSERT(Z_TYPE_P(num) == IS_LONG); // Z_PARAM_NUMBER(num) above guarantee that it's double or float or throw :)
+	zend_long seconds = Z_LVAL_P(num);
+	if (UNEXPECTED(seconds < 0)) {
 		zend_argument_value_error(1, "must be greater than or equal to 0");
 		RETURN_THROWS();
 	}
-
-	RETURN_LONG(php_sleep((unsigned int)num));
+	RETURN_LONG(php_sleep((unsigned int)seconds));
 }
 /* }}} */
 
diff --git a/ext/standard/basic_functions.stub.php b/ext/standard/basic_functions.stub.php
index c3adaceff439..170ba0f424d6 100644
--- a/ext/standard/basic_functions.stub.php
+++ b/ext/standard/basic_functions.stub.php
@@ -1966,7 +1966,7 @@ function getopt(string $short_options, array $long_options = [], &$rest_index =
 
 function flush(): void {}
 
-function sleep(int $seconds): int {}
+function sleep(int|float $seconds): int|float {}
 
 function usleep(int $microseconds): void {}
 
diff --git a/ext/standard/basic_functions_arginfo.h b/ext/standard/basic_functions_arginfo.h
index c420e5c29e0f..1fe783da3808 100644
--- a/ext/standard/basic_functions_arginfo.h
+++ b/ext/standard/basic_functions_arginfo.h
@@ -405,8 +405,8 @@ ZEND_END_ARG_INFO()
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_flush, 0, 0, IS_VOID, 0)
 ZEND_END_ARG_INFO()
 
-ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_sleep, 0, 1, IS_LONG, 0)
-	ZEND_ARG_TYPE_INFO(0, seconds, IS_LONG, 0)
+ZEND_BEGIN_ARG_WITH_RETURN_TYPE_MASK_EX(arginfo_sleep, 0, 1, MAY_BE_LONG|MAY_BE_DOUBLE)
+	ZEND_ARG_TYPE_MASK(0, seconds, MAY_BE_LONG|MAY_BE_DOUBLE, NULL)
 ZEND_END_ARG_INFO()
 
 ZEND_BEGIN_ARG_WITH_RETURN_TYPE_INFO_EX(arginfo_usleep, 0, 1, IS_VOID, 0)
diff --git a/ext/standard/tests/general_functions/sleep_basic.phpt b/ext/standard/tests/general_functions/sleep_basic.phpt
index 98402ad8b21f..276ecde59659 100644
--- a/ext/standard/tests/general_functions/sleep_basic.phpt
+++ b/ext/standard/tests/general_functions/sleep_basic.phpt
@@ -8,6 +8,16 @@ if (getenv("SKIP_SLOW_TESTS")) die("skip slow test");
 <?php
 echo "*** Testing sleep() : basic functionality ***\n";
 
+function have_usleep() {
+// if usleep is not avaiable on the native platform,
+// usleep() calls will just do nothing
+// so to check if we have usleep at runtime, we need to sleep for a short time
+    $t = microtime(true);
+    usleep(10000);
+    return microtime(true) - $t >= 0.009; // 0.009 is 9ms, we asked usleep to sleep for 10ms
+}
+
+
 $sleeptime = 1; // sleep for 1 seconds
 
 set_time_limit(20);
@@ -31,9 +41,31 @@ if ($time >= $sleeplow) {
 } else {
     echo "TEST FAILED - time is {$time} secs and sleep was {$sleeptime} secs\n";
 }
+if (!have_usleep()) {
+    // ¯\_(ツ)_/¯
+    echo "Fractional sleep return value: 0\n";
+    echo "FRACTIONAL SLEEP TEST PASSED\n";
+} else {
+    $time = microtime(true);
+    $result = sleep(0.1);
+    $time = microtime(true) - $time;
+    echo "Fractional sleep return value: " . $result . "\n";
+    if ($time >= 0.09) {
+        echo "FRACTIONAL SLEEP TEST PASSED\n";
+    } else {
+        var_dump([
+            'time' => $time,
+            'result' => $result,
+            'expected_time' => 0.1
+        ]);
+        echo "FRACTIONAL SLEEP TEST FAILED\n";
+    }
+}
 ?>
 --EXPECTF--
 *** Testing sleep() : basic functionality ***
 Thread slept for %f seconds
 Return value: 0
 TEST PASSED
+Fractional sleep return value: 0
+FRACTIONAL SLEEP TEST PASSED