diff --git a/tildes/tildes/templates/includes/topic_tags.jinja2 b/tildes/tildes/templates/includes/topic_tags.jinja2
index 9703163..50f6f42 100644
--- a/tildes/tildes/templates/includes/topic_tags.jinja2
+++ b/tildes/tildes/templates/includes/topic_tags.jinja2
@@ -1,6 +1,6 @@
 <ul class="topic-tags">
   {% for tag in topic.tags %}
-    <li class="label label-topic-tag label-topic-tag-{{ tag }}">
+    <li class="label label-topic-tag label-topic-tag-{{ tag.replace(' ', '_') }}">
       <a href="/~{{ topic.group.path }}?tag={{ tag.replace(' ', '_') }}">{{ tag }}</a>
     </li>
   {% else %}
diff --git a/tildes/tildes/templates/macros/topics.jinja2 b/tildes/tildes/templates/macros/topics.jinja2
index 63980ca..70294ed 100644
--- a/tildes/tildes/templates/macros/topics.jinja2
+++ b/tildes/tildes/templates/macros/topics.jinja2
@@ -34,7 +34,7 @@
       {% if topic.tags %}
         <ul class="topic-tags">
           {% for tag in topic.tags %}
-            <li class="label label-topic-tag label-topic-tag-{{ tag }}">
+            <li class="label label-topic-tag label-topic-tag-{{ tag.replace(' ', '_') }}">
               {% if request.matched_route.name in ('home', 'group') %}
                 <a href="{{ request.current_listing_normal_url({'tag': tag.replace(' ', '_')}) }}">{{ tag }}</a>
               {% else %}