diff --git a/src/index.ts b/src/index.ts
index 1ff2245..0b77555 100755
--- a/src/index.ts
+++ b/src/index.ts
@@ -725,7 +725,7 @@ export class Matcher {
 }
 
 // https://html.spec.whatwg.org/multipage/custom-elements.html#valid-custom-element-name
-const kMarkupPattern = /<!--[^]*?(?=-->)-->|<(\/?)([a-z][-.0-9_a-z]*)\s*([^>]*?)(\/?)>/ig;
+const kMarkupPattern = /<!--[^]*?(?=-->)-->|<(\/?)([a-z][-.:0-9_a-z]*)\s*([^>]*?)(\/?)>/ig;
 const kAttributePattern = /(^|\s)(id|class)\s*=\s*("([^"]+)"|'([^']+)'|(\S+))/ig;
 const kSelfClosingElements = {
 	area: true,
diff --git a/test/html.js b/test/html.js
index d50e7b9..80c54bc 100644
--- a/test/html.js
+++ b/test/html.js
@@ -171,6 +171,11 @@ describe('HTML Parser', function () {
 
 		});
 
+		it('should be able to parse namespaces', function () {
+			const namespacedXML = '<ns:identifier>content</ns:identifier>';
+			parseHTML(namespacedXML).toString().should.eql(namespacedXML);
+		});
+
 		it('should parse "<div><a><img/></a><p></p></div>.." very fast', function () {
 
 			for (var i = 0; i < 100; i++)