diff --git a/lib/jekyll/readers/dynamic/data_reader.rb b/lib/jekyll/readers/dynamic/data_reader.rb
index e436bff4..cbb24be3 100644
--- a/lib/jekyll/readers/dynamic/data_reader.rb
+++ b/lib/jekyll/readers/dynamic/data_reader.rb
@@ -61,9 +61,9 @@ module Jekyll
     end
 
     def sanitize_filename(name)
-      name.gsub!(/[^\w\s_-]+/, '')
+      name.gsub!(/[^\w\s-]+/, '')
       name.gsub!(/(^|\b\s)\s+($|\s?\b)/, '\\1\\2')
       name.gsub(/\s+/, '_')
     end
   end
-end
\ No newline at end of file
+end