diff --git a/README.md b/README.md
index 56127817..f1aadf0a 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,9 @@ spam_checker:
     # this means that spammy messages will appear as empty to users. Default
     # false.
     block_messages: false
+    # Remove users from the user directory search by filtering matrix IDs and
+    # display names by the entries in the user ban list. Default false.
+    block_usernames: false
     # The room IDs of the ban lists to honour. Unlike other parts of Mjolnir,
     # this list cannot be room aliases or permalinks. This server is expected
     # to already be joined to the room - Mjolnir will not automatically join
diff --git a/synapse_antispam/mjolnir/antispam.py b/synapse_antispam/mjolnir/antispam.py
index 2c8dad02..df71fa9b 100644
--- a/synapse_antispam/mjolnir/antispam.py
+++ b/synapse_antispam/mjolnir/antispam.py
@@ -24,6 +24,7 @@ class AntiSpam(object):
     def __init__(self, config, api):
         self.block_invites = config.get("block_invites", True)
         self.block_messages = config.get("block_messages", False)
+        self.block_usernames = config.get("block_usernames", False)
         self.list_room_ids = config.get("ban_lists", [])
         self.rooms_to_lists = {}  # type: Dict[str, BanList]
         self.api = api
@@ -106,6 +107,14 @@ def user_may_invite(self, inviter_user_id, invitee_user_id, room_id):
 
         return True  # allowed (as far as we're concerned)
 
+    def check_username_for_spam(self, user_profile):
+        if not self.block_usernames:
+            return True  # allowed (we aren't blocking based on usernames)
+
+        # Check whether the user ID or display name matches any of the banned
+        # patterns.
+        return self.is_user_banned(user_profile["user_id"]) or self.is_user_banned(user_profile["display_name"])
+
     def user_may_create_room(self, user_id):
         return True  # allowed
 
@@ -115,11 +124,6 @@ def user_may_create_room_alias(self, user_id, room_alias):
     def user_may_publish_room(self, user_id, room_id):
         return True  # allowed
 
-    def check_username_for_spam(self, user_profile):
-        # Check whether the user ID or display name matches any of the banned
-        # patterns.
-        return self.is_user_banned(user_profile["user_id"]) or self.is_user_banned(user_profile["display_name"])
-
     @staticmethod
     def parse_config(config):
         return config  # no parsing needed