diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index f777920950..04ec037184 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -132,7 +132,7 @@ endif()
 
 # silence nvcc warnings
 if((PKG_KOKKOS) AND (Kokkos_ENABLE_CUDA) AND NOT (CMAKE_CXX_COMPILER_ID STREQUAL "Clang"))
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}" "-Xcudafe --diag_suppress=unrecognized_pragma,--diag_suppress=128")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Xcudafe --diag_suppress=unrecognized_pragma,--diag_suppress=128")
 endif()
 
 # we *require* C++11 without extensions but prefer C++17.