diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index 0087e5eabe78..ec7c5dd0eef3 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -1255,6 +1255,10 @@ void UnwrappedLineParser::parseObjCUntilAtEnd() {
       parseBlock(/*MustBeDeclaration=*/false);
       // In ObjC interfaces, nothing should be following the "}".
       addUnwrappedLine();
+    } else if (FormatTok->is(tok::r_brace)) {
+      // Ignore stray "}". parseStructuralElement doesn't consume them.
+      nextToken();
+      addUnwrappedLine();
     } else {
       parseStructuralElement();
     }
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 756c71cf3c24..ea215ab75761 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -5596,6 +5596,10 @@ TEST_F(FormatTest, FormatObjCProtocol) {
                "    int *looooooooooooooooooooooooooooongNumber;\n"
                "@property(nonatomic, assign, readonly)\n"
                "    NSString *looooooooooooooooooooooooooooongName;");
+
+  verifyFormat("@implementation PR18406\n"
+               "}\n"
+               "@end");
 }
 
 TEST_F(FormatTest, FormatObjCMethodDeclarations) {