diff --git a/lib/gitlab/markdown.rb b/lib/gitlab/markdown.rb
index dc9c0e0ab2c..e72f4f5d0ce 100644
--- a/lib/gitlab/markdown.rb
+++ b/lib/gitlab/markdown.rb
@@ -98,7 +98,7 @@ module Gitlab
       (?<prefix>\W)?                         # Prefix
       (                                      # Reference
          @(?<user>[a-zA-Z][a-zA-Z0-9_\-\.]*) # User name
-        |\#(?<issue>([a-zA-Z]+-)?\d+)        # Issue ID
+        |\#(?<issue>([a-zA-Z\-]+-)?\d+)      # Issue ID
         |!(?<merge_request>\d+)              # MR ID
         |\$(?<snippet>\d+)                   # Snippet ID
         |(?<commit>[\h]{6,40})               # Commit ID