diff --git a/programs/psa/CMakeLists.txt b/programs/psa/CMakeLists.txt
index c5d0d28..fd8eeea 100644
--- a/programs/psa/CMakeLists.txt
+++ b/programs/psa/CMakeLists.txt
@@ -9,7 +9,7 @@
         OUTPUT
             ${CMAKE_CURRENT_BINARY_DIR}/psa_constant_names_generated.c
         COMMAND
-            ${PYTHON}
+            ${MBEDTLS_PYTHON_EXECUTABLE}
                 ${CMAKE_CURRENT_SOURCE_DIR}/../../scripts/generate_psa_constants.py
                 ${CMAKE_CURRENT_BINARY_DIR}
         WORKING_DIRECTORY