diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h b/unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h
index 61a4e1a3a..6ca881f27 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorContraction.h
@@ -102,7 +102,7 @@ struct traits<TensorContractionOp<Dimensions, LhsXprType, RhsXprType, OutputKern
   typedef typename remove_reference<RhsNested>::type _RhsNested;
 
   // From NumDims below.
-  static const int NumDimensions = traits<RhsXprType>::NumDimensions + traits<RhsXprType>::NumDimensions - 2 * array_size<Dimensions>::value;
+  static const int NumDimensions = traits<LhsXprType>::NumDimensions + traits<RhsXprType>::NumDimensions - 2 * array_size<Dimensions>::value;
   static const int Layout = traits<LhsXprType>::Layout;
   typedef typename conditional<Pointer_type_promotion<typename LhsXprType::Scalar, Scalar>::val,
   typename traits<LhsXprType>::PointerType, typename traits<RhsXprType>::PointerType>::type PointerType;