diff --git a/test_regress/driver.py b/test_regress/driver.py
index 86ff9f340..65ff4fbe3 100755
--- a/test_regress/driver.py
+++ b/test_regress/driver.py
@@ -1418,7 +1418,7 @@ class VlTest:
             cmd = [
                 "echo q | " + run_env + VtOs.getenv_def('VERILATOR_MODELSIM', "vsim"),
                 ' '.join(param['ms_run_flags']), ' '.join(param['all_run_flags']), pli_opt,
-                (" top")
+                (" t")
             ]
             self.run(cmd=cmd,
                      check_finished=param['check_finished'],
diff --git a/test_regress/t/TestSimulator.h b/test_regress/t/TestSimulator.h
index b99537a78..22fc34cd4 100644
--- a/test_regress/t/TestSimulator.h
+++ b/test_regress/t/TestSimulator.h
@@ -17,11 +17,12 @@
 class TestSimulator {
 private:
     struct SimTypes {
-        int verilator;
-        int icarus;
-        int mti;
-        int ncsim;
-        int vcs;
+        bool verilator = false;
+        bool icarus = false;
+        bool mti = false;
+        bool ncsim = false;
+        bool vcs = false;
+        bool questa = false;
     };
     s_vpi_vlog_info m_info;
     SimTypes m_simulators;
@@ -37,6 +38,8 @@ public:
                    == strncmp(m_info.product, "Chronologic Simulation VCS",
                               std::strlen("Chronologic Simulation VCS"))) {
             m_simulators.vcs = true;
+        } else if (0 == strcmp(m_info.product, "ModelSim for Questa-64")) {
+            m_simulators.questa = true;
         } else {
             printf("%%Warning: %s:%d: Unknown simulator in TestSimulator.h: %s\n", __FILE__,
                    __LINE__, m_info.product);
@@ -59,12 +62,13 @@ public:
     static bool is_mti() { return simulators().mti; }
     static bool is_ncsim() { return simulators().ncsim; }
     static bool is_vcs() { return simulators().vcs; }
+    static bool is_questa() { return simulators().questa; }
     // Simulator properties
     static bool is_event_driven() { return !simulators().verilator; }
     static bool has_get_scalar() { return !simulators().icarus; }
     // return test level scope
     static const char* top() {
-        if (simulators().verilator || simulators().icarus) {
+        if (simulators().verilator || simulators().icarus || simulators().questa) {
             return "t";
         } else {
             return "top.t";