diff -r 0fadf332f0d4 Lib/test/lock_tests.py
--- a/Lib/test/lock_tests.py	Fri Jun 05 21:03:52 2015 -0500
+++ b/Lib/test/lock_tests.py	Sat Jun 06 13:23:20 2015 +0300
@@ -394,6 +394,12 @@ class EventTests(BaseTestCase):
         b.wait_for_finished()
         self.assertEqual(results, [True] * N)
 
+    def test_repr(self):
+        evt = self.eventtype()
+        self.assertRegex(repr(evt), "<unset Event at .*>")
+        evt.set()
+        self.assertRegex(repr(evt), "<set Event at .*>")
+
 
 class ConditionTests(BaseTestCase):
     """
@@ -698,6 +704,15 @@ class SemaphoreTests(BaseSemaphoreTests)
         sem.acquire()
         sem.release()
 
+    def test_repr(self):
+        sem = self.semtype(3)
+        self.assertRegex(repr(sem), "<Semaphore: 3 at .*>")
+        sem.acquire()
+        self.assertRegex(repr(sem), "<Semaphore: 2 at .*>")
+        sem.release()
+        sem.release()
+        self.assertRegex(repr(sem), "<Semaphore: 4 at .*>")
+
 
 class BoundedSemaphoreTests(BaseSemaphoreTests):
     """
@@ -712,6 +727,12 @@ class BoundedSemaphoreTests(BaseSemaphor
         sem.release()
         self.assertRaises(ValueError, sem.release)
 
+    def test_repr(self):
+        sem = self.semtype(3)
+        self.assertRegex(repr(sem), "<BoundedSemaphore: 3/3 at .*>")
+        sem.acquire()
+        self.assertRegex(repr(sem), "<BoundedSemaphore: 2/3 at .*>")
+
 
 class BarrierTests(BaseTestCase):
     """
@@ -904,3 +925,18 @@ class BarrierTests(BaseTestCase):
         b = self.barriertype(1)
         b.wait()
         b.wait()
+
+    def test_repr(self):
+        b = self.barriertype(3)
+        self.assertRegex(repr(b), "<Barrier: 0/3 at .*>")
+        def f():
+            b.wait(3)
+        bunch = Bunch(f, 2)
+        bunch.wait_for_started()
+        time.sleep(0.2)
+        self.assertRegex(repr(b), "<Barrier: 2/3 at .*>")
+        b.wait(3)
+        bunch.wait_for_finished()
+        self.assertRegex(repr(b), "<Barrier: 0/3 at .*>")
+        b.abort()
+        self.assertRegex(repr(b), "<broken Barrier: 0/3 at .*>")
diff -r 0fadf332f0d4 Lib/threading.py
--- a/Lib/threading.py	Fri Jun 05 21:03:52 2015 -0500
+++ b/Lib/threading.py	Sat Jun 06 13:23:20 2015 +0300
@@ -382,6 +382,10 @@ class Semaphore:
         self._cond = Condition(Lock())
         self._value = value
 
+    def __repr__(self):
+        return "<%s: %r at %#x>" % (self.__class__.__name__,
+                                    self._value, id(self))
+
     def acquire(self, blocking=True, timeout=None):
         """Acquire a semaphore, decrementing the internal counter by one.
 
@@ -465,6 +469,11 @@ class BoundedSemaphore(Semaphore):
         Semaphore.__init__(self, value)
         self._initial_value = value
 
+    def __repr__(self):
+        return "<%s: %r/%r at %#x>" % (self.__class__.__name__,
+                                       self._value, self._initial_value,
+                                       id(self))
+
     def release(self):
         """Release a semaphore, incrementing the internal counter by one.
 
@@ -497,6 +506,11 @@ class Event:
         self._cond = Condition(Lock())
         self._flag = False
 
+    def __repr__(self):
+        return '<%s %s at %#x>' % ('set' if self._flag else 'unset',
+                                    self.__class__.__name__,
+                                    id(self))
+
     def _reset_internal_locks(self):
         # private!  called by Thread._reset_internal_locks by _after_fork()
         self._cond.__init__()
@@ -595,6 +609,12 @@ class Barrier:
         self._state = 0 #0 filling, 1, draining, -1 resetting, -2 broken
         self._count = 0
 
+    def __repr__(self):
+        return '<%s%s: %r/%r at %#x>' % ('broken ' if self.broken else '',
+                                         self.__class__.__name__,
+                                         self._count, self._parties,
+                                         id(self))
+
     def wait(self, timeout=None):
         """Wait for the barrier.