diff --git a/mode/xml.py b/mode/xml.py
index d4b7a48..2b351e5 100644
--- a/mode/xml.py
+++ b/mode/xml.py
@@ -20,9 +20,9 @@ class CommentGrammar(Grammar):
     rules = [PatternRule('data', '(?:[^-]|-(?!-)|--(?!>))+')]
 class TagGrammar(Grammar):
     rules = [
-        PatternRule('attrname', '[a-zA-Z_][a-zA-Z0-9_]+(?==)'),
+        PatternRule('attrname', '[a-zA-Z_][-a-zA-Z0-9_]*(?==)'),
         PatternRule('namespace', '[a-zA-Z_]+(?=:)'),
-        PatternRule('name', '[a-zA-Z_][a-zA-Z0-9_]*'),
+        PatternRule('name', '[a-zA-Z_][-a-zA-Z0-9_]*'),
         PatternRule('delimiter', '[:/=]'),
         RegionRule('string', '"', StringGrammar1, '"'),
         RegionRule('string', "'", StringGrammar2, "'"),