diff --git a/src/ruby/ext/grpc/rb_grpc.c b/src/ruby/ext/grpc/rb_grpc.c
index b0ecbce..f138bf6 100644
--- a/src/ruby/ext/grpc/rb_grpc.c
+++ b/src/ruby/ext/grpc/rb_grpc.c
@@ -98,6 +98,7 @@
   const char *tstr = interval ? "time interval" : "time";
   const char *want = " want <secs from epoch>|<Time>|<GRPC::TimeConst.*>";
 
+  t.clock_type = GPR_CLOCK_REALTIME;
   switch (TYPE(time)) {
     case T_DATA:
       if (CLASS_OF(time) == grpc_rb_cTimeVal) {