diff --git a/specification/cognitiveservices/data-plane/QnAMaker/stable/v4.0/QnAMakerRuntime.json b/specification/cognitiveservices/data-plane/QnAMaker/stable/v4.0/QnAMakerRuntime.json
index adc3dd313096..4707f478307c 100644
--- a/specification/cognitiveservices/data-plane/QnAMaker/stable/v4.0/QnAMakerRuntime.json
+++ b/specification/cognitiveservices/data-plane/QnAMaker/stable/v4.0/QnAMakerRuntime.json
@@ -357,6 +357,10 @@
             }
           ]
         },
+       "rankerType": {
+            "type": "string",
+            "description": "Optional field. Set to 'QuestionOnly' for using a question only Ranker."
+        },
         "strictFilters": {
           "type": "array",
           "description": "Find only answers that contain these metadata.",