diff --git a/libcxx/src/chrono.cpp b/libcxx/src/chrono.cpp
--- a/libcxx/src/chrono.cpp
+++ b/libcxx/src/chrono.cpp
@@ -156,6 +156,15 @@
   return steady_clock::time_point(steady_clock::duration(counter.QuadPart * nano::den / freq.QuadPart));
 }
 
+#elif defined(__MVS__)
+
+static steady_clock::time_point __libcpp_steady_clock_now() {
+  timeval tv;
+  gettimeofday(&tv, 0);
+  return steady_clock::time_point(seconds(tv.tv_sec) +
+                                  nanoseconds(tv.tv_usec * 1000));
+}
+
 #elif defined(CLOCK_MONOTONIC)
 
 static steady_clock::time_point __libcpp_steady_clock_now() {