diff --git a/tests/Makefile b/tests/Makefile
index dbba507..ad7affb 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -176,7 +176,7 @@
 				--binary TEST_CLI_KEY_RSA_DER=data_files/cli-rsa.key.der
 
 src/test_keys.h: scripts/generate_test_keys.py
-	scripts/generate_test_keys.py --output $@
+	$(PYTHON) scripts/generate_test_keys.py --output $@
 
 TEST_OBJS_DEPS = $(wildcard include/test/*.h include/test/*/*.h)
 ifdef RECORD_PSA_STATUS_COVERAGE_LOG