diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -2610,6 +2610,7 @@
     nextToken();
     handleAttributes();
     if (FormatTok->is(tok::l_brace)) {
+      const bool FollowedByIf = Tokens->peekNextToken()->is(tok::kw_if);
       FormatTok->setFinalizedType(TT_ElseLBrace);
       ElseLeftBrace = FormatTok;
       CompoundStatementIndenter Indenter(this, Style, Line->Level);
@@ -2621,7 +2622,7 @@
         KeepElseBraces = KeepElseBraces ||
                          ElseBlockKind == IfStmtKind::IfOnly ||
                          ElseBlockKind == IfStmtKind::IfElseIf;
-      } else if (IfLBrace && !IfLBrace->Optional) {
+      } else if (FollowedByIf && IfLBrace && !IfLBrace->Optional) {
         KeepElseBraces = true;
         assert(ElseLeftBrace->MatchingParen);
         markOptionalBraces(ElseLeftBrace);
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -25576,6 +25576,17 @@
                "  g;",
                Style);
 
+  verifyFormat("if (a) {\n"
+               "  b;\n"
+               "  c;\n"
+               "} else { // comment\n"
+               "  if (d) {\n"
+               "    e;\n"
+               "    f;\n"
+               "  }\n"
+               "}",
+               Style);
+
   verifyFormat("if (a)\n"
                "  b;\n"
                "else if (c)\n"