diff --git a/lib/jsduck/js_parser.rb b/lib/jsduck/js_parser.rb
index 1214cfdc146e4939d497198de3c39eb21cdfd504..674884b074167b4e1b88143f19fd167a1d5a54ed 100644
--- a/lib/jsduck/js_parser.rb
+++ b/lib/jsduck/js_parser.rb
@@ -234,7 +234,7 @@ module JsDuck
     end
 
     # <ext-define-cfg> := "{" ( <extend> | <mixins> | <alternate-class-name> | <alias> |
-    #                           <requires> | <uses> | <singleton> | <?> )*
+    #                           <xtype> | <requires> | <uses> | <singleton> | <?> )*
     def ext_define_cfg
       match("{")
       cfg = {}
@@ -249,6 +249,8 @@ module JsDuck
           cfg[:alternateClassNames] = found
         elsif found = ext_define_alias
           cfg[:alias] = found
+        elsif found = ext_define_xtype
+          cfg[:xtype] = found
         elsif found = ext_define_requires
           cfg[:requires] = found
         elsif found = ext_define_uses
@@ -301,6 +303,14 @@ module JsDuck
       end
     end
 
+    # <xtype> := "xtype" ":" <string-or-list>
+    def ext_define_xtype
+      if look("xtype", ":")
+        match("xtype", ":")
+        string_or_list
+      end
+    end
+
     # <requires> := "requires" ":" <string-or-list>
     def ext_define_requires
       if look("requires", ":")
diff --git a/lib/jsduck/merger.rb b/lib/jsduck/merger.rb
index bbe1bd36656c720a976f4d096ff0a6bb6013688f..f32f0d96f346b21a5f2b1cd4bd3b06a9b455369c 100644
--- a/lib/jsduck/merger.rb
+++ b/lib/jsduck/merger.rb
@@ -320,9 +320,16 @@ module JsDuck
     def detect_xtypes(doc_map, code)
       if doc_map[:xtype]
         {"widget" => doc_map[:xtype].map {|tag| tag[:name] } }
-      elsif code[:alias]
+      elsif code[:xtype] || code[:alias]
         xtypes = {}
-        code[:alias].each do |a|
+        (code[:xtype] || []).each do |a|
+          if xtypes["widget"]
+            xtypes["widget"] << a
+          else
+            xtypes["widget"] = [a]
+          end
+        end
+        (code[:alias] || []).each do |a|
           if a =~ /^(\w+)\.(\w+)$/
             if xtypes[$1]
               xtypes[$1] << $2
diff --git a/spec/aggregator_xtypes_spec.rb b/spec/aggregator_xtypes_spec.rb
index 550c04d40b8e181c2f3051f31607581f5d150da1..2b6e7370344e3f3ccfe597ca15a1898f7e553074 100644
--- a/spec/aggregator_xtypes_spec.rb
+++ b/spec/aggregator_xtypes_spec.rb
@@ -114,6 +114,43 @@ describe JsDuck::Aggregator do
     end
   end
 
+  describe "Ext.define() with xtype property" do
+    before do
+      @doc = parse(<<-EOS)[0]
+        /** */
+        Ext.define('MyClass', {
+          xtype: 'foo'
+        });
+      EOS
+    end
+    it_should_behave_like "single xtype"
+  end
+
+  describe "Ext.define() with array xtype property" do
+    before do
+      @doc = parse(<<-EOS)[0]
+        /** */
+        Ext.define('MyClass', {
+          xtype: ['foo', 'bar']
+        });
+      EOS
+    end
+    it_should_behave_like "multiple xtypes"
+  end
+
+  describe "Ext.define() with both xtype and alias" do
+    before do
+      @doc = parse(<<-EOS)[0]
+        /** */
+        Ext.define('MyClass', {
+          xtype: 'foo',
+          alias: 'widget.bar'
+        });
+      EOS
+    end
+    it_should_behave_like "multiple xtypes"
+  end
+
   describe "one class many times" do
     before do
       @doc = parse(<<-EOS)[0]