diff --git a/unsupported/Eigen/CXX11/Tensor b/unsupported/Eigen/CXX11/Tensor
index f88ddc514..5251ff9e4 100644
--- a/unsupported/Eigen/CXX11/Tensor
+++ b/unsupported/Eigen/CXX11/Tensor
@@ -40,6 +40,7 @@
 #include <cstring>
 #include <random>
 #include <thread>
+#include <numeric>
 
 #if defined(EIGEN_USE_THREADS) || defined(EIGEN_USE_SYCL)
 #include "ThreadPool"