diff --git a/CHANGES.rst b/CHANGES.rst
index 48666f31a1..9d423c033e 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -36,6 +36,10 @@ Unreleased
 * The file for ModActions (praw/models/modaction.py) has been moved to
   praw/models/mod_action.py and the previous has been Deprecated.
 
+**Removed**
+
+* The `_unmute` parameter of :meth:`.SubredditMessage.mute` was removed.
+
 **Expected Changes**
 
 * The behavior of :class:`.APIException` will no longer unicode-escape strings
diff --git a/praw/models/reddit/message.py b/praw/models/reddit/message.py
index d013287ef0..d100977a0c 100644
--- a/praw/models/reddit/message.py
+++ b/praw/models/reddit/message.py
@@ -95,7 +95,7 @@ def delete(self):
 class SubredditMessage(Message):
     """A class for messages to a subreddit."""
 
-    def mute(self, _unmute=False):
+    def mute(self):
         """Mute the sender of this SubredditMessage."""
         self._reddit.post(API_PATH["mute_sender"], data={"id": self.fullname})