diff --git a/Lib/threading.py b/Lib/threading.py
--- a/Lib/threading.py
+++ b/Lib/threading.py
@@ -314,33 +314,31 @@
 
     def acquire(self, blocking=1):
         rc = False
-        self.__cond.acquire()
-        while self.__value == 0:
-            if not blocking:
-                break
-            if __debug__:
-                self._note("%s.acquire(%s): blocked waiting, value=%s",
-                           self, blocking, self.__value)
-            self.__cond.wait()
-        else:
-            self.__value = self.__value - 1
-            if __debug__:
-                self._note("%s.acquire: success, value=%s",
-                           self, self.__value)
-            rc = True
-        self.__cond.release()
+        with self.__cond:
+            while self.__value == 0:
+                if not blocking:
+                    break
+                if __debug__:
+                    self._note("%s.acquire(%s): blocked waiting, value=%s",
+                            self, blocking, self.__value)
+                self.__cond.wait()
+            else:
+                self.__value = self.__value - 1
+                if __debug__:
+                    self._note("%s.acquire: success, value=%s",
+                            self, self.__value)
+                rc = True
         return rc
 
     __enter__ = acquire
 
     def release(self):
-        self.__cond.acquire()
-        self.__value = self.__value + 1
-        if __debug__:
-            self._note("%s.release: success, value=%s",
-                       self, self.__value)
-        self.__cond.notify()
-        self.__cond.release()
+        with self.__cond:
+            self.__value = self.__value + 1
+            if __debug__:
+                self._note("%s.release: success, value=%s",
+                        self, self.__value)
+            self.__cond.notify()
 
     def __exit__(self, t, v, tb):
         self.release()
@@ -383,28 +381,19 @@
     is_set = isSet
 
     def set(self):
-        self.__cond.acquire()
-        try:
+        with self.__cond:
             self.__flag = True
             self.__cond.notify_all()
-        finally:
-            self.__cond.release()
 
     def clear(self):
-        self.__cond.acquire()
-        try:
+        with self.__cond:
             self.__flag = False
-        finally:
-            self.__cond.release()
 
     def wait(self, timeout=None):
-        self.__cond.acquire()
-        try:
+        with self.__cond:
             if not self.__flag:
                 self.__cond.wait(timeout)
             return self.__flag
-        finally:
-            self.__cond.release()
 
 # Helper to generate new thread names
 _counter = 0