diff --git a/python/tools/prepare_test_environment.sh b/python/tools/prepare_test_environment.sh
index c2f516cd8..599e4c673 100755
--- a/python/tools/prepare_test_environment.sh
+++ b/python/tools/prepare_test_environment.sh
@@ -4,6 +4,7 @@ set -e
 set -x
 
 # Install test rquirements
+pip cache purge
 pip --no-cache-dir install -r python/tests/requirements.txt --extra-index-url https://download.pytorch.org/whl/cpu
 pip uninstall -y ctranslate2