diff --git a/lib/Format/UnwrappedLineParser.cpp b/lib/Format/UnwrappedLineParser.cpp
index 7f9e97e..f1d08a6 100644
--- a/lib/Format/UnwrappedLineParser.cpp
+++ b/lib/Format/UnwrappedLineParser.cpp
@@ -311,6 +311,18 @@
   case tok::kw_return:
     parseReturn();
     return;
+  case tok::kw_extern:
+    nextToken();
+    if (FormatTok.Tok.is(tok::string_literal)) {
+      nextToken();
+      if (FormatTok.Tok.is(tok::l_brace)) {
+        parseBlock(0);
+        addUnwrappedLine();
+        return;
+      }
+    }
+    // In all other cases, parse the declaration.
+    break;
   default:
     break;
   }
diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index f8c454b..f67cd8c 100644
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -526,6 +526,10 @@
                "void f() { f(); }");
 }
 
+TEST_F(FormatTest, FormatsExternC) {
+  verifyFormat("extern \"C\" {\nint a;");
+}
+
 TEST_F(FormatTest, FormatTryCatch) {
   // FIXME: Handle try-catch explicitly in the UnwrappedLineParser, then we'll
   // also not create single-line-blocks.