diff --git a/roles/tox/tasks/siblings.yaml b/roles/tox/tasks/siblings.yaml
index a838f2e59..33ba98828 100644
--- a/roles/tox/tasks/siblings.yaml
+++ b/roles/tox/tasks/siblings.yaml
@@ -9,6 +9,7 @@
     {% if tox_envlist is defined and tox_envlist %}
     -e{{ tox_envlist }}
     {% endif %}
+    {{ tox_extra_args }}
   args:
     chdir: "{{ zuul_work_dir }}"
   environment: "{{ tox_environment|combine(tox_constraints_env|default({})) }}"
@@ -28,6 +29,7 @@
     {% if tox_envlist is defined and tox_envlist %}
     -e{{ tox_envlist }}
     {% endif %}
+    {{ tox_extra_args }}
     > {{ _tox_show_config_tempfile.path }}
   args:
     chdir: "{{ zuul_work_dir }}"