diff --git a/python-package/xgboost/sklearn.py b/python-package/xgboost/sklearn.py
index ea7fb0585..895aeadb4 100644
--- a/python-package/xgboost/sklearn.py
+++ b/python-package/xgboost/sklearn.py
@@ -1783,6 +1783,10 @@ class XGBRFRegressor(XGBRegressor):
     "Implementation of the Scikit-Learn API for XGBoost Ranking.",
     ["estimators", "model"],
     end_note="""
+        .. note::
+
+            The default objectivefor XGBRanker is "rank:pairwise"
+
         .. note::
 
             A custom objective function is currently not supported by XGBRanker.