diff --git a/python-package/xgboost/core.py b/python-package/xgboost/core.py
index 0c07671e5..062627365 100644
--- a/python-package/xgboost/core.py
+++ b/python-package/xgboost/core.py
@@ -844,7 +844,7 @@ class DMatrix(object):
 
 
 class Booster(object):
-    """A Booster of of XGBoost.
+    """A Booster of XGBoost.
 
     Booster is the model of xgboost, that contains low level routines for
     training, prediction and evaluation.