diff --git a/lib/oga.rb b/lib/oga.rb
index 5bc0e6a..83537c7 100644
--- a/lib/oga.rb
+++ b/lib/oga.rb
@@ -25,8 +25,8 @@ require_relative 'oga/xml/cdata'
 require_relative 'oga/xml/xml_declaration'
 require_relative 'oga/xml/processing_instruction'
 require_relative 'oga/xml/doctype'
-require_relative 'oga/xml/attribute'
 require_relative 'oga/xml/namespace'
+require_relative 'oga/xml/attribute'
 require_relative 'oga/xml/element'
 require_relative 'oga/xml/node_set'
 
diff --git a/lib/oga/xml/attribute.rb b/lib/oga/xml/attribute.rb
index 1acefb2..7f0c99f 100644
--- a/lib/oga/xml/attribute.rb
+++ b/lib/oga/xml/attribute.rb
@@ -21,6 +21,17 @@ module Oga
     class Attribute
       attr_accessor :name, :namespace_name, :element, :value
 
+      ##
+      # The default namespace available to all attributes. This namespace can
+      # not be modified.
+      #
+      # @return [Oga::XML::Namespace]
+      #
+      DEFAULT_NAMESPACE = Namespace.new(
+        :name => 'xml',
+        :uri  => 'http://www.w3.org/XML/1998/namespace'
+      ).freeze
+
       ##
       # @param [Hash] options
       #
@@ -44,7 +55,15 @@ module Oga
       # @return [Oga::XML::Namespace]
       #
       def namespace
-        return @namespace ||= element.available_namespaces[namespace_name]
+        unless @namespace
+          if namespace_name == DEFAULT_NAMESPACE.name
+            @namespace = DEFAULT_NAMESPACE
+          else
+            @namespace = element.available_namespaces[namespace_name]
+          end
+        end
+
+        return @namespace
       end
 
       ##
diff --git a/spec/oga/xml/attribute_spec.rb b/spec/oga/xml/attribute_spec.rb
index be08cf7..8d9bdb0 100644
--- a/spec/oga/xml/attribute_spec.rb
+++ b/spec/oga/xml/attribute_spec.rb
@@ -24,11 +24,17 @@ describe Oga::XML::Attribute do
         :name           => 'a',
         :element        => element
       )
+
+      @default = described_class.new(:namespace_name => 'xml', :name => 'x')
     end
 
     example 'return a Namespace instance' do
       @attribute.namespace.should == @namespace
     end
+
+    example 'return the default XML namespace when the "xml" prefix is used' do
+      @default.namespace.should == Oga::XML::Attribute::DEFAULT_NAMESPACE
+    end
   end
 
   context '#to_s' do