diff --git a/rtl/Makefile b/rtl/Makefile
index ce54a935..1a6e41fc 100644
--- a/rtl/Makefile
+++ b/rtl/Makefile
@@ -5,7 +5,7 @@ all: RUNFILE
 
 
 VERILATOR:
-	verilator -Wall -cc Vortex.v --exe test_bench.cpp 
+	verilator -Wall -cc Vortex.v --exe test_bench.cpp -CFLAGS std=c++11
 
 RUNFILE: VERILATOR
 	(cd obj_dir && make -j -f VVortex.mk)