diff --git a/aip/general/0203.md b/aip/general/0203.md
index 55ffcac4b0..4643c09d99 100644
--- a/aip/general/0203.md
+++ b/aip/general/0203.md
@@ -28,6 +28,8 @@ RecognitionAudio audio = 2 [(google.api.field_behavior) = REQUIRED];
   on a message or sub-message used in a request.
   - An exception to this is the AIP-154 `etag` field on a resource message,
     which **should not** have any `google.api.field_behavior` assigned.
+  - Furthermore, `oneof` fields **may** omit `google.api.field_behavior`, but
+    **should** document any specific behaviors in the comments in this case.
 - The annotation **must** include any [google.api.FieldBehavior][] values that
   accurately describe the behavior of the field.
   - `FIELD_BEHAVIOR_UNSPECIFIED` **must not** be used.