diff --git a/README.rst b/README.rst
index 79b8b18..0db113f 100644
--- a/README.rst
+++ b/README.rst
@@ -51,6 +51,11 @@
             home_dir_mode: 755
             email: 'jonh@doe.com'
             unique: false
+            groups:
+            - db-ops
+            - salt-ops
+            optional_groups:
+            - docker
           jsmith:
             name: 'jsmith'
             enabled: true
diff --git a/linux/system/user.sls b/linux/system/user.sls
index 42086d5..64636f3 100644
--- a/linux/system/user.sls
+++ b/linux/system/user.sls
@@ -45,6 +45,9 @@
   {%- if user.groups is defined %}
   - groups: {{ user.groups }}
   {%- endif %}
+  {%- if user.optional_groups is defined %}
+  - optional_groups: {{ user.optional_groups }}
+  {%- endif %}
   {%- if user.system is defined and user.system %}
   - system: True
   - shell: {{ user.get('shell', '/bin/false') }}
diff --git a/tests/pillar/system.sls b/tests/pillar/system.sls
index de1da29..6a0b16b 100644
--- a/tests/pillar/system.sls
+++ b/tests/pillar/system.sls
@@ -141,6 +141,8 @@
         groups:
           - db-ops
           - salt-ops
+        optional_groups:
+        - docker
       salt_user1:
         enabled: true
         name: saltuser1