diff --git a/Eigen/src/Core/products/Parallelizer.h b/Eigen/src/Core/products/Parallelizer.h
index 420f88ca6..ecdedc363 100644
--- a/Eigen/src/Core/products/Parallelizer.h
+++ b/Eigen/src/Core/products/Parallelizer.h
@@ -30,7 +30,7 @@ namespace internal {
 /** \internal */
 inline void manage_multi_threading(Action action, int* v)
 {
-  static int m_maxThreads = -1;
+  static EIGEN_UNUSED int m_maxThreads = -1;
 
   if(action==SetAction)
   {