diff --git a/external/librett.cmake b/external/librett.cmake
index aa1287d90d..9774a84152 100644
--- a/external/librett.cmake
+++ b/external/librett.cmake
@@ -37,11 +37,6 @@ else()
 
     message("** Will clone LibreTT from ${LIBRETT_URL}")
 
-    # need to change the separator of list to avoid issues with ExternalProject parsing
-#    set(CUDA_FLAGS "${CUDA_NVCC_FLAGS}")
-#    string(REPLACE ";" "::" CUDA_FLAGS "${CUDA_NVCC_FLAGS}")
-    #message(STATUS "CUDA_FLAGS: " "${CUDA_FLAGS}")
-
     set(LIBRETT_CMAKE_ARGS
         -DCMAKE_INSTALL_PREFIX=${EXTERNAL_INSTALL_DIR}
         -DBUILD_SHARED_LIBS=${BUILD_SHARED_LIBS}
@@ -62,22 +57,37 @@ else()
         -DCMAKE_CXX_STANDARD=${CMAKE_CXX_STANDARD}
         -DCMAKE_CXX_EXTENSIONS=${CMAKE_CXX_EXTENSIONS}
         -DCMAKE_AR=${CMAKE_AR}
-        -DCMAKE_CUDA_COMPILER=${CMAKE_CUDA_COMPILER}
-        -DCMAKE_CUDA_STANDARD=${CMAKE_CUDA_STANDARD}
-        -DCMAKE_CUDA_EXTENSIONS=${CMAKE_CUDA_EXTENSIONS}
         -DENABLE_UMPIRE=OFF
         # N.B. ThreadSafeUMDynamicPool this no longer exists!!! Must teach LibreTT to take allocate/deallocate methods
         # from the user code
         -DLIBRETT_USES_THIS_UMPIRE_ALLOCATOR=ThreadSafeUMDynamicPool
         -DCMAKE_PREFIX_PATH=${_UMPIRE_INSTALL_DIR}
         -DENABLE_NO_ALIGNED_ALLOC=ON
-        -DCMAKE_CUDA_HOST_COMPILER=${CMAKE_CUDA_HOST_COMPILER}
-        -DCUDA_TOOLKIT_ROOT_DIR=${CUDAToolkit_ROOT}
-	    -DENABLE_CUDA=ON
         )
-    if (DEFINED CMAKE_CUDA_ARCHITECTURES)
-        list(APPEND LIBRETT_CMAKE_ARGS -DCMAKE_CUDA_ARCHITECTURES=${CMAKE_CUDA_ARCHITECTURES})
-    endif(DEFINED CMAKE_CUDA_ARCHITECTURES)
+    if (ENABLE_CUDA)
+        list(APPEND LIBRETT_CMAKE_ARGS
+                -DENABLE_CUDA=ON
+                -DCMAKE_CUDA_COMPILER=${CMAKE_CUDA_COMPILER}
+                -DCMAKE_CUDA_STANDARD=${CMAKE_CUDA_STANDARD}
+                -DCMAKE_CUDA_EXTENSIONS=${CMAKE_CUDA_EXTENSIONS}
+                -DCMAKE_CUDA_HOST_COMPILER=${CMAKE_CUDA_HOST_COMPILER}
+                -DCUDA_TOOLKIT_ROOT_DIR=${CUDAToolkit_ROOT}
+        )
+        if (DEFINED CMAKE_CUDA_ARCHITECTURES)
+            list(APPEND LIBRETT_CMAKE_ARGS -DCMAKE_CUDA_ARCHITECTURES=${CMAKE_CUDA_ARCHITECTURES})
+        endif(DEFINED CMAKE_CUDA_ARCHITECTURES)
+    endif()
+    if (ENABLE_HIP)
+        list(APPEND LIBRETT_CMAKE_ARGS
+                -DENABLE_HIP=ON
+                -DCMAKE_HIP_COMPILER=${CMAKE_HIP_COMPILER}
+                -DCMAKE_HIP_STANDARD=${CMAKE_HIP_STANDARD}
+                -DCMAKE_HIP_EXTENSIONS=${CMAKE_HIP_EXTENSIONS}
+        )
+        if (DEFINED CMAKE_HIP_ARCHITECTURES)
+            list(APPEND LIBRETT_CMAKE_ARGS -DCMAKE_HIP_ARCHITECTURES=${CMAKE_HIP_ARCHITECTURES})
+        endif(DEFINED CMAKE_HIP_ARCHITECTURES)
+    endif()
     if (CMAKE_TOOLCHAIN_FILE)
         set(LIBRETT_CMAKE_ARGS "${LIBRETT_CMAKE_ARGS}"
             "-DCMAKE_TOOLCHAIN_FILE=${CMAKE_TOOLCHAIN_FILE}")
@@ -147,9 +157,21 @@ set_target_properties(TiledArray_LIBRETT
         "$<BUILD_INTERFACE:${EXTERNAL_SOURCE_DIR}/src>;$<INSTALL_INTERFACE:${_LIBRETT_INSTALL_DIR}/include>"
         INTERFACE_LINK_LIBRARIES
         "$<BUILD_INTERFACE:${LIBRETT_BUILD_BYPRODUCTS}>;$<INSTALL_INTERFACE:${_LIBRETT_INSTALL_DIR}/lib/librett.${LIBRETT_DEFAULT_LIBRARY_SUFFIX}>"
-        INTERFACE_COMPILE_DEFINITIONS
-        "LIBRETT_USES_CUDA=1"
         )
+if (ENABLE_CUDA)
+    set_target_properties(TiledArray_LIBRETT
+            PROPERTIES
+            INTERFACE_COMPILE_DEFINITIONS
+            "LIBRETT_USES_CUDA=1"
+    )
+endif()
+if (ENABLE_HIP)
+    set_target_properties(TiledArray_LIBRETT
+            PROPERTIES
+            INTERFACE_COMPILE_DEFINITIONS
+            "LIBRETT_USES_HIP=1"
+    )
+endif()
 
 install(TARGETS TiledArray_LIBRETT EXPORT tiledarray COMPONENT tiledarray)