diff --git a/lib/ansible/modules/cloud/openstack/os_subnet.py b/lib/ansible/modules/cloud/openstack/os_subnet.py
index d3f805fba2..45faf271c1 100644
--- a/lib/ansible/modules/cloud/openstack/os_subnet.py
+++ b/lib/ansible/modules/cloud/openstack/os_subnet.py
@@ -95,6 +95,12 @@ options:
    availability_zone:
      description:
        - Ignored. Present for backwards compatibility
+   extra_specs:
+     description:
+        - Dictionary with extra key/value pairs passed to the API
+     required: false
+     default: {}
+     version_added: "2.7"
 requirements:
     - "python >= 2.6"
     - "openstacksdk"
@@ -231,6 +237,7 @@ def main():
         ipv6_ra_mode=dict(default=None, choice=ipv6_mode_choices),
         ipv6_address_mode=dict(default=None, choice=ipv6_mode_choices),
         use_default_subnetpool=dict(default=False, type='bool'),
+        extra_specs=dict(required=False, default=dict(), type='dict'),
         state=dict(default='present', choices=['absent', 'present']),
         project=dict(default=None)
     )
@@ -256,6 +263,7 @@ def main():
     ipv6_a_mode = module.params['ipv6_address_mode']
     use_default_subnetpool = module.params['use_default_subnetpool']
     project = module.params.pop('project')
+    extra_specs = module.params['extra_specs']
 
     # Check for required parameters when state == 'present'
     if state == 'present':
@@ -296,6 +304,7 @@ def main():
         if state == 'present':
             if not subnet:
                 kwargs = dict(
+                    cidr=cidr,
                     ip_version=ip_version,
                     enable_dhcp=enable_dhcp,
                     subnet_name=subnet_name,
@@ -307,9 +316,14 @@ def main():
                     ipv6_ra_mode=ipv6_ra_mode,
                     ipv6_address_mode=ipv6_a_mode,
                     tenant_id=project_id)
+                dup_args = set(kwargs.keys()) & set(extra_specs.keys())
+                if dup_args:
+                    raise ValueError('Duplicate key(s) {0} in extra_specs'
+                                     .format(list(dup_args)))
                 if use_default_subnetpool:
                     kwargs['use_default_subnetpool'] = use_default_subnetpool
-                subnet = cloud.create_subnet(network_name, cidr, **kwargs)
+                kwargs = dict(kwargs, **extra_specs)
+                subnet = cloud.create_subnet(network_name, **kwargs)
                 changed = True
             else:
                 if _needs_update(subnet, module, cloud):