diff --git a/clang-tools-extra/clang-tidy/cert/VariadicFunctionDefCheck.cpp b/clang-tools-extra/clang-tidy/cert/VariadicFunctionDefCheck.cpp
index ac788a3aee5c..a5f8fa7e7334 100644
--- a/clang-tools-extra/clang-tidy/cert/VariadicFunctionDefCheck.cpp
+++ b/clang-tools-extra/clang-tidy/cert/VariadicFunctionDefCheck.cpp
@@ -20,9 +20,12 @@ void VariadicFunctionDefCheck::registerMatchers(MatchFinder *Finder) {
   if (!getLangOpts().CPlusPlus)
     return;
 
-  // We only care about function *definitions* that are variadic.
-  Finder->addMatcher(functionDecl(isDefinition(), isVariadic()).bind("func"),
-                     this);
+  // We only care about function *definitions* that are variadic, and do not
+  // have extern "C" language linkage.
+  Finder->addMatcher(
+      functionDecl(isDefinition(), isVariadic(), unless(isExternC()))
+          .bind("func"),
+      this);
 }
 
 void VariadicFunctionDefCheck::check(const MatchFinder::MatchResult &Result) {
diff --git a/clang-tools-extra/test/clang-tidy/cert-variadic-function-def.cpp b/clang-tools-extra/test/clang-tidy/cert-variadic-function-def.cpp
index 6bb6b1371b86..2c1420b9e362 100644
--- a/clang-tools-extra/test/clang-tidy/cert-variadic-function-def.cpp
+++ b/clang-tools-extra/test/clang-tidy/cert-variadic-function-def.cpp
@@ -16,3 +16,9 @@ struct S {
   void f1(int, ...) {}
   // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: do not define a C-style variadic function; consider using a function parameter pack or currying instead
 };
+
+// Function definitions that are extern "C" are good.
+extern "C" void f4(int, ...) {} // ok
+extern "C" {
+  void f5(int, ...) {} // ok
+}