diff --git a/Core.Tests/Parser/ParsingTests.cs b/Core.Tests/Parser/ParsingTests.cs
index f3098f8..2c8f6bc 100644
--- a/Core.Tests/Parser/ParsingTests.cs
+++ b/Core.Tests/Parser/ParsingTests.cs
@@ -222,6 +222,21 @@ public void BadClosingTag ()
 			result.AssertDiagnosticCount (2);
 		}
 
+		[Test]
+		public void MalformedSelfClosingTag ()
+		{
+			var parser = new XmlTreeParser (CreateRootState ());
+			var result = parser.Parse (@"<root / $>",
+
+				() => {
+					parser.AssertStateIs<XmlTagState> ();
+				});
+
+			parser.AssertDiagnostics (
+				(XmlCoreDiagnostics.MalformedSelfClosingTag, 7, 0)
+				);
+		}
+
 		[Test]
 		public void MismatchedElementNameWithNamespace ()
 		{
diff --git a/Core/Parser/XmlTagState.cs b/Core/Parser/XmlTagState.cs
index d9c98e3..9a1869f 100644
--- a/Core/Parser/XmlTagState.cs
+++ b/Core/Parser/XmlTagState.cs
@@ -41,7 +41,7 @@ public class XmlTagState : XmlParserState
 
 		const int ATTEMPT_RECOVERY = 1;
 		const int RECOVERY_FOUND_WHITESPACE = 2;
-		const int MAYBE_SELF_CLOSING = 2;
+		const int MAYBE_SELF_CLOSING = 3;
 		const int FREE = 0;
 
 		readonly XmlAttributeState AttributeState;
@@ -139,6 +139,11 @@ public XmlTagState (XmlAttributeState attributeState, XmlNameState nameState)
 				return null;
 			}
 
+			if (context.StateTag == MAYBE_SELF_CLOSING) {
+				context.Diagnostics?.Add (XmlCoreDiagnostics.MalformedSelfClosingTag, context.Position, c);
+				return null;
+			}
+
 			if (context.StateTag == ATTEMPT_RECOVERY) {
 				if (XmlChar.IsWhitespace (c)) {
 					context.StateTag = RECOVERY_FOUND_WHITESPACE;