diff --git a/requests/sessions.py b/requests/sessions.py
index 0d1441bb..36a760dd 100644
--- a/requests/sessions.py
+++ b/requests/sessions.py
@@ -365,7 +365,12 @@ class Session(SessionRedirectMixin):
                 return adapter
 
         # Nothing matches :-/
-        raise InvalidSchema('No connection adapters were found for \'%s\'' % url)
+        raise InvalidSchema("No connection adapters were found for '%s'" % url)
+
+    def close(self):
+        """Closes all adapters and as such the session"""
+        for _, v in self.adapters.items():
+            v.close()
 
     def mount(self, prefix, adapter):
         """Registers a connection adapter to a prefix."""