diff --git a/external/umpire.cmake b/external/umpire.cmake
index ee2fa490e1..5b7a4f4078 100644
--- a/external/umpire.cmake
+++ b/external/umpire.cmake
@@ -223,6 +223,8 @@ else()
             "$<BUILD_INTERFACE:${EXTERNAL_SOURCE_DIR}/src>;$<BUILD_INTERFACE:${EXTERNAL_SOURCE_DIR}/src/tpl>;$<BUILD_INTERFACE:${EXTERNAL_SOURCE_DIR}/src/tpl/umpire/camp/include>;$<BUILD_INTERFACE:${EXTERNAL_SOURCE_DIR}/src/tpl/umpire/fmt/include>;$<BUILD_INTERFACE:${EXTERNAL_BUILD_DIR}/src/tpl/umpire/camp/include>;$<BUILD_INTERFACE:${EXTERNAL_BUILD_DIR}/include>;$<INSTALL_INTERFACE:${_UMPIRE_INSTALL_DIR}/include>"
             INTERFACE_LINK_LIBRARIES
             "$<BUILD_INTERFACE:${UMPIRE_BUILD_BYPRODUCTS}>;$<INSTALL_INTERFACE:${_UMPIRE_INSTALL_DIR}/lib/libumpire${UMPIRE_DEFAULT_LIBRARY_SUFFIX}>"
+            INTERFACE_COMPILE_DEFINITIONS
+            FMT_HEADER_ONLY=1
             )
 
 install(TARGETS TiledArray_UMPIRE EXPORT tiledarray COMPONENT tiledarray)