diff --git a/.azure-pipelines/templates/steps/tox-steps.yml b/.azure-pipelines/templates/steps/tox-steps.yml
index 2878ecbde..caf9194c0 100644
--- a/.azure-pipelines/templates/steps/tox-steps.yml
+++ b/.azure-pipelines/templates/steps/tox-steps.yml
@@ -22,7 +22,7 @@ steps:
     inputs:
       versionSpec: $(PYTHON_VERSION)
       addToPath: true
-    condition: not(variables['PYTHON_VERSION'])
+    condition: not(eq(variables['PYTHON_VERSION'], ''))
   - bash: |
       python tools/pip_install.py -I tox virtualenv
     displayName: Install runtime dependencies