diff --git a/usr.bin/grep/zgrep.sh b/usr.bin/grep/zgrep.sh
index a39084eb84d4..8cc49f952912 100755
--- a/usr.bin/grep/zgrep.sh
+++ b/usr.bin/grep/zgrep.sh
@@ -106,6 +106,10 @@ do
 	    silent=1
 	    shift
 	    ;;
+	-r|-R)
+	    echo "${prg}: the ${1} flag is not currently supported" >&2
+	    exit 1
+	    ;;
 	-V|--version)
 	    exec ${grep} -V
 	    ;;