diff --git a/Tools/jmavsim_run.sh b/Tools/jmavsim_run.sh
index b04912afdd..d792a27cf8 100755
--- a/Tools/jmavsim_run.sh
+++ b/Tools/jmavsim_run.sh
@@ -50,7 +50,7 @@ else
 fi
 
 if [ "$HEADLESS" = "1" ]; then
-    extra_args="$extr_args -no-gui"
+    extra_args="$extra_args -no-gui"
 fi
 
 # jMAVSim crashes with Java 9 on macOS, therefore we need to use Java 8