diff --git a/scintilla/lexers/LexMarkdown.cxx b/scintilla/lexers/LexMarkdown.cxx
index 87adb65766..1b70b44c8c 100644
--- a/scintilla/lexers/LexMarkdown.cxx
+++ b/scintilla/lexers/LexMarkdown.cxx
@@ -1222,11 +1222,18 @@ bool MarkdownLexer::HighlightAutoLink() {
 				break;
 
 			case SCE_H_COMMENT:
-				invalid = sc.Match('-', '-', '>');
+				if (sc.Match('-', '-')) {
+					const char chNext = sc.styler[sc.currentPos + 2];
+					if (chNext == '>' || chNext == '?') {
+						invalid = true;
+					}
+				}
 				break;
 
 			case SCE_H_CDATA:
-				invalid = sc.Match(']', ']', '>');
+				if (sc.Match(']', ']', '>')) {
+					invalid = true;
+				}
 				break;
 			}
 		}
@@ -1313,6 +1320,13 @@ bool MarkdownLexer::HandleHtmlTag(HtmlTagType tagType) {
 		if (chNext == '-' && sc.GetRelative(3) == '-') {
 			sc.SetState(SCE_H_COMMENT);
 			sc.Advance(3);
+			// handle empty comment: <!-->, <!--->
+			// https://html.spec.whatwg.org/multipage/parsing.html#parse-error-abrupt-closing-of-empty-comment
+			if (sc.chNext == '>' || sc.MatchNext('-', '>')) {
+				sc.Forward((sc.chNext == '>') ? 2 : 3);
+				sc.SetState(current);
+				return true;
+			}
 		} else if (chNext == '[' && sc.styler.Match(sc.currentPos + 3, "CDATA[")) {
 			// <![CDATA[ ]]>
 			sc.SetState(SCE_H_CDATA);
@@ -2276,11 +2290,18 @@ void ColouriseMarkdownDoc(Sci_PositionU startPos, Sci_Position lengthDoc, int in
 			break;
 
 		case SCE_H_COMMENT:
-			if (sc.Match('-', '-', '>')) {
-				lexer.tagState = HtmlTagState::None;
-				sc.Advance(3);
-				sc.SetState(lexer.TryTakeOuterStyle());
-				continue;
+			if (sc.Match('-', '-')) {
+				do {
+					sc.Forward();
+				} while (sc.ch == '-');
+				// close HTML comment with --!>
+				// https://html.spec.whatwg.org/multipage/parsing.html#parse-error-incorrectly-closed-comment
+				if (sc.ch == '>' || sc.Match('!', '>')) {
+					lexer.tagState = HtmlTagState::None;
+					sc.Forward((sc.ch == '>') ? 1 : 2);
+					sc.SetState(lexer.TryTakeOuterStyle());
+					continue;
+				}
 			}
 			lexer.DetectAutoLink();
 			break;