diff --git a/heat/engine/resources/openstack/nova/host_aggregate.py b/heat/engine/resources/openstack/nova/host_aggregate.py
index 2b6f0ce81b..ee57fe27bb 100644
--- a/heat/engine/resources/openstack/nova/host_aggregate.py
+++ b/heat/engine/resources/openstack/nova/host_aggregate.py
@@ -56,7 +56,6 @@ class HostAggregate(resource.Resource):
         AVAILABILITY_ZONE: properties.Schema(
             properties.Schema.STRING,
             _('Name for the availability zone.'),
-            required=True,
             update_allowed=True,
         ),
         HOSTS: properties.Schema(
diff --git a/releasenotes/notes/correct-availability-zone-to-be-non-mandatory-b01192007d5e0386.yaml b/releasenotes/notes/correct-availability-zone-to-be-non-mandatory-b01192007d5e0386.yaml
new file mode 100644
index 0000000000..9e0716e90a
--- /dev/null
+++ b/releasenotes/notes/correct-availability-zone-to-be-non-mandatory-b01192007d5e0386.yaml
@@ -0,0 +1,8 @@
+---
+fixes:
+  - |
+    Erroneously, availability_zone for host aggregate resource types was
+    considered mandatory in heat templates.
+
+    Behaviour has been adjusted to bring this in line with the CLI and GUI, in
+    which it is optional.