diff --git a/fastapi/openapi/utils.py b/fastapi/openapi/utils.py
index 88786087a..9d5c98e88 100644
--- a/fastapi/openapi/utils.py
+++ b/fastapi/openapi/utils.py
@@ -417,11 +417,13 @@ def get_openapi_path(
                     openapi_response["description"] = description
             http422 = "422"
             all_route_params = get_flat_params(route.dependant)
-            requires_validation_error = bool(all_route_params or route.body_field)
-            has_validation_response = any(
-                status in operation["responses"] for status in ("422", "4XX", "default")
-            )
-            if requires_validation_error and not has_validation_response:
+            if (
+                (all_route_params or route.body_field)  # May raise validation error
+                and not any(  # Doesn't have a defined validation error response already
+                    status in operation["responses"]
+                    for status in [http422, "4XX", "default"]
+                )
+            ):
                 operation["responses"][http422] = {
                     "description": "Validation Error",
                     "content": {