diff --git a/app/helpers/tree_helper.rb b/app/helpers/tree_helper.rb
index a5d5c7422302e2e50f9127305f9d9f1f3d323415..2b7265ca19e42e074f5517c13e75dd52fefc69d1 100644
--- a/app/helpers/tree_helper.rb
+++ b/app/helpers/tree_helper.rb
@@ -32,7 +32,11 @@ module TreeHelper
   #
   # Returns boolean
   def markup?(filename)
-    filename.end_with?(*%w(.mdown .md .markdown .textile .rdoc .org .creole
-                          .mediawiki .rst .asciidoc .pod))
+    filename.end_with?(*%w(.textile .rdoc .org .creole
+                           .mediawiki .rst .asciidoc .pod))
+  end
+
+  def gitlab_markdown?(filename)
+    filename.end_with?(*%w(.mdown .md .markdown))
   end
 end
diff --git a/app/views/refs/_tree.html.haml b/app/views/refs/_tree.html.haml
index ec6dba4ee07a318e1072a95718035883fc5e08bb..55078718b79f26793100b0bc507612e1dee55166 100644
--- a/app/views/refs/_tree.html.haml
+++ b/app/views/refs/_tree.html.haml
@@ -43,7 +43,11 @@
           %i.icon-file
           = content.name
         .file_content.wiki
-          = raw GitHub::Markup.render(content.name, content.data)
+          - if gitlab_markdown?(content.name)
+            = preserve do
+              = markdown(content.data)
+          - else
+            = raw GitHub::Markup.render(content.name, content.data)
 
 :javascript
   $(function(){
diff --git a/app/views/refs/_tree_file.html.haml b/app/views/refs/_tree_file.html.haml
index f6566ccf5d528bb5e3da02926d6b4ed5dea5501c..76173e24246ac9d1d64472887dec068e0a68cf91 100644
--- a/app/views/refs/_tree_file.html.haml
+++ b/app/views/refs/_tree_file.html.haml
@@ -9,7 +9,11 @@
       = link_to "history", project_commits_path(@project, path: params[:path], ref: @ref), class: "btn very_small"
       = link_to "blame", blame_file_project_ref_path(@project, @ref, path: params[:path]), class: "btn very_small"
   - if file.text?
-    - if markup?(name)
+    - if gitlab_markdown?(name)
+      .file_content.wiki
+        = preserve do
+          = markdown(file.data)
+    - elsif markup?(name)
       .file_content.wiki
         = raw GitHub::Markup.render(name, file.data)
     - else