diff --git a/bin/shtests b/bin/shtests
index 713102998..03bf8ab6b 100755
--- a/bin/shtests
+++ b/bin/shtests
@@ -7,7 +7,20 @@
 # Brief help: bin/shtests --help
 #
 # By default, this runs your compiled arch/*/bin/ksh.
-# To use another ksh, run:  KSH=path/to/ksh bin/shtests
+#
+# Note: The test suite actually uses $SHELL to indicate the shell to test. But
+# we cannot use the $SHELL environment value on entry to this wrapper script,
+# as that is already used for the user's default login shell on most systems.
+
+# Process and remove any assignment-argument indicating the shell to test
+for arg do
+	case $arg in
+	( SHELL=* | KSH=* )
+		KSH=${arg#*=} ;;
+	( * )	set -- "$@" "$1" ;;
+	esac
+	shift
+done
 
 # Find root dir of ksh source
 mydir=$(dirname "$0") \