diff --git a/src/ng/compile.js b/src/ng/compile.js
index 2f5eadfc5919..a1002b1cc627 100644
--- a/src/ng/compile.js
+++ b/src/ng/compile.js
@@ -512,8 +512,8 @@ $CompileProvider.$inject = ['$provide', '$$sanitizeUriProvider'];
 function $CompileProvider($provide, $$sanitizeUriProvider) {
   var hasDirectives = {},
       Suffix = 'Directive',
-      COMMENT_DIRECTIVE_REGEXP = /^\s*directive\:\s*([\d\w\-_]+)\s+(.*)$/,
-      CLASS_DIRECTIVE_REGEXP = /(([\d\w\-_]+)(?:\:([^;]+))?;?)/;
+      COMMENT_DIRECTIVE_REGEXP = /^\s*directive\:\s*([\d\w_\-]+)\s+(.*)$/,
+      CLASS_DIRECTIVE_REGEXP = /(([\d\w_\-]+)(?:\:([^;]+))?;?)/;
 
   // Ref: http://developers.whatwg.org/webappapis.html#event-handler-idl-attributes
   // The assumption is that future DOM event attribute names will begin with