diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -2288,8 +2288,12 @@
 
 void Clang::AddWebAssemblyTargetArgs(const ArgList &Args,
                                      ArgStringList &CmdArgs) const {
-  // Default to "hidden" visibility.
-  if (!Args.hasArg(options::OPT_fvisibility_EQ,
+  const llvm::Triple &T = getToolChain().getTriple();
+  // Default to "hidden" visibility for WebAssembly targets except
+  // for emscripten which uses the default for compatibility with
+  // existing code.
+  if (T.getOS() != llvm::Triple::Emscripten &&
+      !Args.hasArg(options::OPT_fvisibility_EQ,
                    options::OPT_fvisibility_ms_compat)) {
     CmdArgs.push_back("-fvisibility");
     CmdArgs.push_back("hidden");
diff --git a/clang/test/Driver/wasm-toolchain.c b/clang/test/Driver/wasm-toolchain.c
--- a/clang/test/Driver/wasm-toolchain.c
+++ b/clang/test/Driver/wasm-toolchain.c
@@ -12,6 +12,10 @@
 // RUN:   | FileCheck -check-prefix=FVISIBILITY_DEFAULT %s
 // FVISIBILITY_DEFAULT-NOT: hidden
 
+// Emscripten is different in that it defaults to default, like other non-WebAssembly targets.
+// RUN: %clang %s -### -target wasm32-unknown-emscripten 2>&1 \
+// RUN:   | FileCheck -check-prefix=FVISIBILITY_DEFAULT %s
+
 // A basic C link command-line with unknown OS.
 
 // RUN: %clang -### -no-canonical-prefixes -target wasm32-unknown-unknown --sysroot=/foo %s 2>&1 \