diff --git a/openstackclient/compute/v2/flavor.py b/openstackclient/compute/v2/flavor.py
index 76635e12b0..c0e043e8f1 100644
--- a/openstackclient/compute/v2/flavor.py
+++ b/openstackclient/compute/v2/flavor.py
@@ -156,12 +156,25 @@ class CreateFlavor(command.ShowOne):
             msg = _("--project is only allowed with --private")
             raise exceptions.CommandError(msg)
 
+        flavor_id = parsed_args.id
+        if parsed_args.id == 'auto':
+            # novaclient aliased 'auto' to mean "generate a UUID for me": we
+            # do the same to avoid breaking existing users
+            flavor_id = None
+
+            msg = _(
+                "Passing '--id auto' is deprecated. Nova will automatically "
+                "assign a UUID-like ID if no ID is provided. Omit the '--id' "
+                "parameter instead."
+            )
+            self.log.warning(msg)
+
         args = {
             'name': parsed_args.name,
             'ram': parsed_args.ram,
             'vcpus': parsed_args.vcpus,
             'disk': parsed_args.disk,
-            'id': parsed_args.id,
+            'id': flavor_id,
             'ephemeral': parsed_args.ephemeral,
             'swap': parsed_args.swap,
             'rxtx_factor': parsed_args.rxtx_factor,
diff --git a/openstackclient/tests/unit/compute/v2/test_flavor.py b/openstackclient/tests/unit/compute/v2/test_flavor.py
index e7e6bab709..0b3a4ae8d3 100644
--- a/openstackclient/tests/unit/compute/v2/test_flavor.py
+++ b/openstackclient/tests/unit/compute/v2/test_flavor.py
@@ -247,7 +247,7 @@ class TestFlavorCreate(TestFlavor):
             'ram': self.flavor.ram,
             'vcpus': self.flavor.vcpus,
             'disk': self.flavor.disk,
-            'id': 'auto',
+            'id': None,
             'ephemeral': self.flavor.ephemeral,
             'swap': self.flavor.swap,
             'rxtx_factor': self.flavor.rxtx_factor,
diff --git a/releasenotes/notes/flavor-id-auto-e21157f97dc1d7f2.yaml b/releasenotes/notes/flavor-id-auto-e21157f97dc1d7f2.yaml
new file mode 100644
index 0000000000..96b56b8df6
--- /dev/null
+++ b/releasenotes/notes/flavor-id-auto-e21157f97dc1d7f2.yaml
@@ -0,0 +1,6 @@
+---
+deprecations:
+  - |
+    The ``--id auto`` alias for the ``flavor create`` command is deprecated
+    for removal. Omit the option entirely to ensure the server creates the
+    ID for you.