diff --git a/lib/oga/xml/lexer.rl b/lib/oga/xml/lexer.rl
index 6afa0c4..6bca0eb 100644
--- a/lib/oga/xml/lexer.rl
+++ b/lib/oga/xml/lexer.rl
@@ -255,7 +255,7 @@ module Oga
 
         newline    = '\n' | '\r\n';
         whitespace = [ \t];
-        identifier = [a-zA-Z0-9\-_]+;
+        identifier = [a-zA-Z0-9\-_:]+;
 
         # Strings
         #
@@ -470,8 +470,7 @@ module Oga
           fcall element_head;
         }
 
-        element_name  = [a-zA-Z0-9\-_:]+;
-        element_start = '<' element_name;
+        element_start = '<' identifier;
 
         # Machine used for processing the characters inside a element head. An
         # element head is everything between `<NAME` (where NAME is the element
@@ -515,7 +514,7 @@ module Oga
           };
 
           # Regular closing tags.
-          '</' element_name '>' => {
+          '</' identifier '>' => {
             emit_buffer
             add_token(:T_ELEM_END, nil)
 
diff --git a/spec/oga/xml/lexer/elements_spec.rb b/spec/oga/xml/lexer/elements_spec.rb
index 1e7e5f4..19bb346 100644
--- a/spec/oga/xml/lexer/elements_spec.rb
+++ b/spec/oga/xml/lexer/elements_spec.rb
@@ -73,6 +73,16 @@ describe Oga::XML::Lexer do
         [:T_ELEM_END, nil, 1]
       ]
     end
+
+    example 'lex a paragraph element with a namespaced attribute' do
+      lex('<p foo:bar="baz"></p>').should == [
+        [:T_ELEM_START, nil, 1],
+        [:T_ELEM_NAME, 'p', 1],
+        [:T_ATTR, 'foo:bar', 1],
+        [:T_STRING, 'baz', 1],
+        [:T_ELEM_END, nil, 1]
+      ]
+    end
   end
 
   context 'nested elements' do