diff --git a/zerver/lib/webhooks/common.py b/zerver/lib/webhooks/common.py
index 2232e401ea..6e40943fc2 100644
--- a/zerver/lib/webhooks/common.py
+++ b/zerver/lib/webhooks/common.py
@@ -1,3 +1,5 @@
+from urllib.parse import unquote
+
 from django.conf import settings
 from django.http import HttpRequest
 from django.utils.translation import ugettext as _
@@ -51,7 +53,8 @@ class MissingHTTPEventHeader(JsonableError):
 def check_send_webhook_message(
         request: HttpRequest, user_profile: UserProfile,
         topic: str, body: str, stream: Optional[str]=REQ(default=None),
-        user_specified_topic: Optional[str]=REQ("topic", default=None)
+        user_specified_topic: Optional[str]=REQ("topic", default=None),
+        unquote_stream: Optional[bool]=False
 ) -> None:
 
     if stream is None:
@@ -59,6 +62,13 @@ def check_send_webhook_message(
         check_send_private_message(user_profile, request.client,
                                    user_profile.bot_owner, body)
     else:
+        # Some third-party websites (such as Atlassian's JIRA), tend to
+        # double escape their URLs in a manner that escaped space characters
+        # (%20) are never properly decoded. We work around that by making sure
+        # that the stream name is decoded on our end.
+        if unquote_stream:
+            stream = unquote(stream)
+
         if user_specified_topic is not None:
             topic = user_specified_topic
 
diff --git a/zerver/webhooks/jira/tests.py b/zerver/webhooks/jira/tests.py
index 9b81b7e30e..b9dd7fe423 100644
--- a/zerver/webhooks/jira/tests.py
+++ b/zerver/webhooks/jira/tests.py
@@ -1,5 +1,7 @@
 # -*- coding: utf-8 -*-
 
+from urllib.parse import quote, unquote
+
 from zerver.lib.test_classes import WebhookTestCase
 from zerver.lib.users import get_api_key
 
@@ -28,6 +30,24 @@ class JiraHookTests(WebhookTestCase):
         self.send_and_test_stream_message('created_v1', expected_subject, expected_message)
         self.send_and_test_stream_message('created_v2', expected_subject, expected_message)
 
+    def test_created_with_stream_with_spaces_escaped(self) -> None:
+        self.STREAM_NAME = quote('jira alerts')
+        self.url = self.build_webhook_url()
+        self.subscribe(self.test_user, unquote(self.STREAM_NAME))
+
+        payload = self.get_body('created_v1')
+        result = self.client_post(self.url, payload, content_type='application/json')
+
+        self.assert_json_success(result)
+
+        expected_subject = "BUG-15: New bug with hook"
+        expected_message = """Leo Franchi **created** [BUG-15](http://lfranchi.com:8080/browse/BUG-15) priority Major, assigned to **no one**:
+
+> New bug with hook"""
+        msg = self.get_last_message()
+        self.assertEqual(msg.content, expected_message)
+        self.assertEqual(msg.topic_name(), expected_subject)
+
     def test_created_with_unicode(self) -> None:
             expected_subject = u"BUG-15: New bug with à hook"
             expected_message = u"""Leo Franchià **created** [BUG-15](http://lfranchi.com:8080/browse/BUG-15) priority Major, assigned to **no one**:
diff --git a/zerver/webhooks/jira/view.py b/zerver/webhooks/jira/view.py
index 04259663d1..96b37f3800 100644
--- a/zerver/webhooks/jira/view.py
+++ b/zerver/webhooks/jira/view.py
@@ -241,5 +241,7 @@ def api_jira_webhook(request: HttpRequest, user_profile: UserProfile,
     else:
         raise UnexpectedWebhookEventType('Jira', event)
 
-    check_send_webhook_message(request, user_profile, subject, content)
+    check_send_webhook_message(request, user_profile,
+                               subject, content,
+                               unquote_stream=True)
     return json_success()