diff --git a/flang/lib/Frontend/CompilerInvocation.cpp b/flang/lib/Frontend/CompilerInvocation.cpp
--- a/flang/lib/Frontend/CompilerInvocation.cpp
+++ b/flang/lib/Frontend/CompilerInvocation.cpp
@@ -107,6 +107,14 @@
   // By default the frontend driver creates a ParseSyntaxOnly action.
   opts.programAction = ParseSyntaxOnly;
 
+  // Treat multiple action options as an invocation error.
+  if (args.hasMultipleArgs(clang::driver::options::OPT_Action_Group)) {
+    const unsigned diagID = diags.getCustomDiagID(
+        clang::DiagnosticsEngine::Error, "Only one action option is allowed");
+    diags.Report(diagID);
+    return false;
+  }
+
   // Identify the action (i.e. opts.ProgramAction)
   if (const llvm::opt::Arg *a =
           args.getLastArg(clang::driver::options::OPT_Action_Group)) {
diff --git a/flang/test/Driver/multiple-actions-error.f95 b/flang/test/Driver/multiple-actions-error.f95
new file mode 100644
--- /dev/null
+++ b/flang/test/Driver/multiple-actions-error.f95
@@ -0,0 +1,8 @@
+! Verify that the frontend driver error-out if multiple actions are specified
+
+! RUN: not %flang_fc1 -E -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix=ERROR
+! RUN: not %flang_fc1 -fsyntax-only -fsyntax-only %s 2>&1 | FileCheck %s --check-prefix=ERROR
+
+! ERROR: error: Only one action option is allowed
+
+end progream
diff --git a/llvm/include/llvm/Option/ArgList.h b/llvm/include/llvm/Option/ArgList.h
--- a/llvm/include/llvm/Option/ArgList.h
+++ b/llvm/include/llvm/Option/ArgList.h
@@ -245,6 +245,12 @@
     return getLastArg(Ids...) != nullptr;
   }
 
+  /// Return true if the arg list contains multiple arguments matching \p Id.
+  bool hasMultipleArgs(OptSpecifier Id) const {
+    auto Args = filtered(Id);
+    return (++Args.begin()) != Args.end();
+  }
+
   /// Return the last argument matching \p Id, or null.
   template<typename ...OptSpecifiers>
   Arg *getLastArg(OptSpecifiers ...Ids) const {