diff --git a/CMake/itkExternal_Eigen3.cmake b/CMake/itkExternal_Eigen3.cmake
index 276a90187e0..bbf313ce001 100644
--- a/CMake/itkExternal_Eigen3.cmake
+++ b/CMake/itkExternal_Eigen3.cmake
@@ -50,6 +50,7 @@ else()
     "-DCMAKE_C_FLAGS=${CMAKE_C_FLAGS}"
     "-DCMAKE_CXX_COMPILER=${CMAKE_CXX_COMPILER}"
     "-DCMAKE_CXX_FLAGS=${CMAKE_CXX_FLAGS}"
+    "-DCMAKE_OSX_ARCHITECTURES=${CMAKE_OSX_ARCHITECTURES}"
     ${_additional_external_project_args}
     WORKING_DIRECTORY ${_eigen3_build_dir}
     OUTPUT_VARIABLE ITKEigen3Config_STDOUT