diff --git a/jobrunner/mail/chat.py b/jobrunner/mail/chat.py
index 07c6a29..b90bb00 100644
--- a/jobrunner/mail/chat.py
+++ b/jobrunner/mail/chat.py
@@ -77,7 +77,7 @@ class PostError(Exception):
     pass
 
 
-def _postToGChat(text, uri, threadId=None):
+def _postToGChat(text, uri, timeout, threadId=None):
     payload = {
         "text": text,
     }
@@ -86,7 +86,7 @@ def _postToGChat(text, uri, threadId=None):
     }
     if threadId:
         payload["thread"] = {"name": threadId}
-    ret = requests.post(uri, json=payload, headers=headers)
+    ret = requests.post(uri, json=payload, headers=headers, timeout=timeout)
     try:
         return ret.json()["thread"]["name"]
     except (KeyError, TypeError):
@@ -154,6 +154,9 @@ def parseArgs(args=None):
     ap.add_argument("-f", dest="inFile", action="store")
     ap.add_argument("-T", "--new-thread", action="store_true",
                     help="Do not re-use the previous chat thread for each hook")
+    ap.add_argument("--timeout", type=int, default=10,
+                    help="Specify timeout (in seconds) for REST API requests "
+                    "(default=%(default)s)")
     ap.add_argument("toAddr", metavar="to-addr", nargs="+")
 
     return ap.parse_args(args)
@@ -191,7 +194,7 @@ def main(args=None):
                     if not opts.new_thread and config.chatmailReuseThreads
                     else None)
 
-        newThreadId = _postToGChat(msg, hook, threadId=threadId)
+        newThreadId = _postToGChat(msg, hook, opts.timeout, threadId=threadId)
         threadCache.put(hook, newThreadId)
 
     return OK
diff --git a/jobrunner/test/chatmail_test.py b/jobrunner/test/chatmail_test.py
index e952ebc..7ebff29 100644
--- a/jobrunner/test/chatmail_test.py
+++ b/jobrunner/test/chatmail_test.py
@@ -13,6 +13,8 @@
 
 # pylint: disable-msg=protected-access
 
+TIMEOUT = 10
+
 
 @patch("jobrunner.mail.chat.requests", new=MagicMock(requests))
 class ChatPostTest(TestCase):
@@ -21,7 +23,7 @@ def testGoodRequest(self):
         chat.requests.post = MagicMock(return_value=retMock)
         retMock.json.return_value = {"thread": {"name": "somethread"}}
         self.assertEqual(
-            chat._postToGChat("foo", "https://something"),
+            chat._postToGChat("foo", "https://something", TIMEOUT),
             "somethread")
 
     def testBadRequestReturn(self):
@@ -36,7 +38,7 @@ def testBadRequestReturn(self):
         for retVal in retValues:
             retMock.json.return_value = retVal
             self.assertEqual(
-                chat._postToGChat("foo", "https://something"),
+                chat._postToGChat("foo", "https://something", TIMEOUT),
                 None)
 
 
@@ -93,7 +95,7 @@ def assertPostTextMatchesRegexp(self, regexp, callIdx=0):
 
     def testRequestSafetySanity(self, *_):
         with self.assertRaises(AttributeError):
-            chat.requests.post()
+            chat.requests.post("http://example.com/foo")
 
     def testBasicCall(self, *mockArgs):
         mocks = ChatTest.Mocks(mockArgs)
@@ -102,7 +104,7 @@ def testBasicCall(self, *mockArgs):
 
         chat.main(["user1"])
 
-        mocks.postToGChat.assert_called_once_with(ANY, hook, threadId=None)
+        mocks.postToGChat.assert_called_once_with(ANY, hook, TIMEOUT, threadId=None)
         self.assertPostTextMatchesRegexp("NO SUBJECT")
 
     def testBasicCallWithOptions(self, *mockArgs):
@@ -123,7 +125,7 @@ def testBasicCallWithOptions(self, *mockArgs):
                 openMock.assert_called_once_with("mytext.txt")
 
         self.assertEqual(ret, 0)
-        mocks.postToGChat.assert_called_once_with(ANY, hook, threadId=None)
+        mocks.postToGChat.assert_called_once_with(ANY, hook, TIMEOUT, threadId=None)
         self.assertPostTextMatchesRegexp(
             r"My subject.*a bunch of\ntext.*attachfile.txt")
 
@@ -140,7 +142,8 @@ def testPipeContent(self, *mockArgs):
             ret = chat.main(["-s", "My subject", "user1"])
 
             self.assertEqual(ret, 0)
-            mocks.postToGChat.assert_called_once_with(ANY, hook, threadId=None)
+            mocks.postToGChat.assert_called_once_with(ANY, hook, TIMEOUT,
+                                                      threadId=None)
             self.assertPostTextMatchesRegexp(
                 r"\*My subject\*" + (r"\s*$" if tty else r".*a bunch of\ntext"))
 
@@ -159,7 +162,7 @@ def testCallWithMultipleHooks(self, *mockArgs):
                          "user1", "user2"])
 
         self.assertEqual(ret, 0)
-        calls = [call(ANY, hook, threadId=None)
+        calls = [call(ANY, hook, TIMEOUT, threadId=None)
                  for hook in set(hooks.values())]
         self.assertEqual(mocks.postToGChat.call_count, len(calls))
         mocks.postToGChat.assert_has_calls(calls, any_order=True)
@@ -196,7 +199,7 @@ def _runTest(retThreadId, reuseThreads):
 
             self.assertEqual(ret, 0)
             mocks.postToGChat.assert_called_once_with(
-                ANY, hook,
+                ANY, hook, TIMEOUT,
                 threadId=threadId if reuseThreads else None)
             if threadId == retThreadId:
                 self.assertEqual(mocks.threadCacheWrite.call_count, 0)
@@ -224,7 +227,8 @@ def _runTest(atAllConfig, userIdDict, expectAtAll=False):
             ret = chat.main(["-s", "My subject"] + users)
 
             self.assertEqual(ret, 0)
-            mocks.postToGChat.assert_called_once_with(ANY, hook, threadId=None)
+            mocks.postToGChat.assert_called_once_with(ANY, hook, TIMEOUT,
+                                                      threadId=None)
             pattern = r"\*My subject\*"
             tags = []
             if expectAtAll: