diff --git a/include/verilated.cpp b/include/verilated.cpp
index e3a847edc..1ad503beb 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -1678,7 +1678,7 @@ void Verilated::flushCall() VL_MT_SAFE {
 }
 
 void Verilated::commandArgs(int argc, const char** argv) VL_MT_SAFE {
-    VerilatedLockGuard lock(m_mutex);
+    VerilatedLockGuard lock(s_args.m_argMutex);
     s_args.argc = argc;
     s_args.argv = argv;
     VerilatedImp::commandArgs(argc,argv);
diff --git a/include/verilated.h b/include/verilated.h
index 998740bfc..6d869ea5e 100644
--- a/include/verilated.h
+++ b/include/verilated.h
@@ -347,6 +347,7 @@ class Verilated {
     // no need to be save-restored (serialized) the
     // assumption is that the restore is allowed to pass different arguments
     static struct CommandArgValues {
+        VerilatedMutex m_argMutex;  ///< Mutex for s_args members, when VL_THREADED
 	int          argc;
 	const char** argv;
         CommandArgValues() : argc(0), argv(NULL) {}