diff --git a/Lib/multiprocessing/synchronize.py b/Lib/multiprocessing/synchronize.py
index 9188114ae284c7..d445138fa9234f 100644
--- a/Lib/multiprocessing/synchronize.py
+++ b/Lib/multiprocessing/synchronize.py
@@ -125,22 +125,89 @@ def _make_name():
         return '%s-%s' % (process.current_process()._config['semprefix'],
                           next(SemLock._rand))
 
+if sys.platform == 'darwin':
+    #
+    # Specific MacOSX Semaphore
+    #
+
+    class _MacOSXSemaphore(SemLock):
+        """Dedicated class used only to workaround the missing
+        function 'sem_getvalue', when interpreter runs on MacOSX.
+        Add two shared counters for each [Bounded]Semaphore in order
+        to calculate the internal value of the semaphore,
+        when acquire and release operations are called.
+        """
+
+        def __init__(self, kind, value, maxvalue, *, ctx):
+            if not isinstance(self, Semaphore):
+                raise TypeError("_MacOSXSemaphore can only be used "
+                                "as base class of Semaphore class")
+            self._rlock = ctx.RLock()
+            self._count = ctx.Value('h', value, lock=self._rlock)
+            self._pending_acquires = ctx.Value('h', 0, lock=self._rlock)
+            super().__init__(kind, value, maxvalue, ctx=ctx)
+
+        def acquire(self, blocking=True, timeout=None):
+            with self._rlock:
+                self._pending_acquires.value += 1
+            if self._semlock.acquire(blocking, timeout):
+                with self._rlock:
+                    self._pending_acquires.value -= 1
+                    self._count.value -= 1
+                return True
+            with self._rlock:
+                self._pending_acquires.value -= 1
+            return False
+
+        def release(self):
+            if isinstance(self, BoundedSemaphore):
+                with self._rlock:
+                    if self.get_value() + 1 > self._semlock.maxvalue:
+                        raise ValueError(f"semaphore released too many times")
+            with self._rlock:
+                self._count.value += 1
+                self._semlock.release()
+
+        def get_value(self):
+            with self._rlock:
+                val = self._count.value - self._pending_acquires.value
+                return val if val > 0 else 0
+
+        def _make_methods(self):
+            # Do not call the `Semlock._make_methods` method,
+            # because that breaks the reference to the local
+            # `acquire` and `release` methods.
+            pass
+
+        def __setstate__(self, state):
+            self._count, self._pending_acquires, self._rlock, state \
+                = state[-3], state[-2], state[-1], state[:-3]
+            super().__setstate__(state)
+
+        def __getstate__(self) -> tuple:
+            return super().__getstate__() \
+                + (self._count, self._pending_acquires, self._rlock)
+
+
+    _SemClass = _MacOSXSemaphore
+else:
+    class _NotMacOSXSemaphore(SemLock):
+        def __init__(self, kind, value, maxvalue, *, ctx):
+            super().__init__(kind, value, maxvalue, ctx=ctx)
+
+        def get_value(self) -> int:
+            return self._semlock._get_value()
+
+    _SemClass = _NotMacOSXSemaphore
+
 #
 # Semaphore
 #
 
-class Semaphore(SemLock):
+class Semaphore(_SemClass):
 
     def __init__(self, value=1, *, ctx):
-        SemLock.__init__(self, SEMAPHORE, value, SEM_VALUE_MAX, ctx=ctx)
-
-    def get_value(self):
-        '''Returns current value of Semaphore.
-
-        Raises NotImplementedError on Mac OSX
-        because of broken sem_getvalue().
-        '''
-        return self._semlock._get_value()
+        _SemClass.__init__(self, SEMAPHORE, value, SEM_VALUE_MAX, ctx=ctx)
 
     def __repr__(self):
         try:
@@ -156,7 +223,7 @@ def __repr__(self):
 class BoundedSemaphore(Semaphore):
 
     def __init__(self, value=1, *, ctx):
-        SemLock.__init__(self, SEMAPHORE, value, value, ctx=ctx)
+        _SemClass.__init__(self, SEMAPHORE, value, value, ctx=ctx)
 
     def __repr__(self):
         try:
diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index 580d9f2b32544e..d8e4a58090ce89 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -1750,10 +1750,26 @@ def test_semaphore(self):
     def test_bounded_semaphore(self):
         sem = self.BoundedSemaphore(2)
         self._test_semaphore(sem)
-        # Currently fails on OS/X
-        #if HAVE_GETVALUE:
-        #    self.assertRaises(ValueError, sem.release)
-        #    self.assertReturnsIfImplemented(2, get_value, sem)
+        self.assertRaises(ValueError, sem.release)
+        self.assertReturnsIfImplemented(2, get_value, sem)
+
+    @unittest.skipIf(sys.platform != 'darwin', 'Darwin only')
+    def test_detect_macosx_semaphore(self):
+        if self.TYPE != 'processes':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        sem = self.Semaphore(2)
+        mro = sem.__class__.mro()
+        self.assertTrue(any('_MacOSXSemaphore' in cls.__name__ for cls in mro))
+
+    @unittest.skipIf(sys.platform != 'darwin', 'Darwin only')
+    def test_detect_macosx_boundedsemaphore(self):
+        if self.TYPE != 'processes':
+            self.skipTest('test not appropriate for {}'.format(self.TYPE))
+
+        sem = self.BoundedSemaphore(2)
+        mro = sem.__class__.mro()
+        self.assertTrue(any('_MacOSXSemaphore' in cls.__name__ for cls in mro))
 
     def test_timeout(self):
         if self.TYPE != 'processes':
diff --git a/Misc/NEWS.d/next/Library/2026-01-26-16-18-19.gh-issue-125828.W6BLH8.rst b/Misc/NEWS.d/next/Library/2026-01-26-16-18-19.gh-issue-125828.W6BLH8.rst
new file mode 100644
index 00000000000000..ef02f1b55a9074
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2026-01-26-16-18-19.gh-issue-125828.W6BLH8.rst
@@ -0,0 +1 @@
+Fix the unimplemented ``get_value`` method of the ``_multiprocessing.SemLock`` class on MacOSX by adding a specific inherited class between ``multiprocessing.SemLock`` and :class:`multiprocessing.Semaphore`.
diff --git a/Programs/test_frozenmain.h b/Programs/test_frozenmain.h
index 1bcf98a7600851..0f07d03b05a329 100644
--- a/Programs/test_frozenmain.h
+++ b/Programs/test_frozenmain.h
@@ -13,10 +13,10 @@ unsigned char M_test_frozenmain[] = {
     92,2,31,0,81,4,92,6,12,0,81,5,92,5,92,6,
     42,26,0,0,0,0,0,0,0,0,0,0,12,0,48,4,
     50,1,0,0,0,0,0,0,29,0,74,26,0,0,9,0,
-    28,0,80,7,33,0,41,7,233,0,0,0,0,122,18,70,
+    28,0,80,7,33,0,41,7,233,0,0,0,0,218,18,70,
     114,111,122,101,110,32,72,101,108,108,111,32,87,111,114,108,
-    100,122,8,115,121,115,46,97,114,103,118,218,6,99,111,110,
-    102,105,103,122,7,99,111,110,102,105,103,32,122,2,58,32,
+    100,218,8,115,121,115,46,97,114,103,118,218,6,99,111,110,
+    102,105,103,218,7,99,111,110,102,105,103,32,218,2,58,32,
     41,5,218,12,112,114,111,103,114,97,109,95,110,97,109,101,
     218,10,101,120,101,99,117,116,97,98,108,101,218,15,117,115,
     101,95,101,110,118,105,114,111,110,109,101,110,116,218,17,99,
@@ -25,15 +25,15 @@ unsigned char M_test_frozenmain[] = {
     41,7,218,3,115,121,115,218,17,95,116,101,115,116,105,110,
     116,101,114,110,97,108,99,97,112,105,218,5,112,114,105,110,
     116,218,4,97,114,103,118,218,11,103,101,116,95,99,111,110,
-    102,105,103,115,114,3,0,0,0,218,3,107,101,121,169,0,
+    102,105,103,115,114,5,0,0,0,218,3,107,101,121,169,0,
     243,0,0,0,0,218,18,116,101,115,116,95,102,114,111,122,
     101,110,109,97,105,110,46,112,121,218,8,60,109,111,100,117,
-    108,101,62,114,18,0,0,0,1,0,0,0,115,94,0,0,
+    108,101,62,114,22,0,0,0,1,0,0,0,115,94,0,0,
     0,241,3,1,1,1,243,8,0,1,11,219,0,24,225,0,
     5,208,6,26,212,0,27,217,0,5,128,106,144,35,151,40,
     145,40,212,0,27,216,9,26,215,9,38,210,9,38,211,9,
     40,168,24,213,9,50,128,6,244,2,6,12,2,128,67,241,
     14,0,5,10,136,71,144,67,144,53,152,2,152,54,160,35,
     157,59,152,45,208,10,40,214,4,41,243,15,6,12,2,114,
-    16,0,0,0,
+    20,0,0,0,
 };