diff -Naurp a/jpegxl.cmake b/jpegxl.cmake
--- a/jpegxl.cmake	2020-02-27 00:53:11.000000000 +0000
+++ b/jpegxl.cmake	2020-02-27 00:53:13.000000000 +0000
@@ -437,9 +437,9 @@ endif()  # APPLE
 install(TARGETS jpegxl
   DESTINATION ${CMAKE_INSTALL_LIBDIR})
 install(DIRECTORY ${CMAKE_SOURCE_DIR}/include/jpegxl
-  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/jpegxl")
+  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
 install(DIRECTORY ${CMAKE_BINARY_DIR}/include/jpegxl
-  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/jpegxl")
+  DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}")
 
 # Add a pkg-config file for libjpegxl.
 configure_file("${CMAKE_SOURCE_DIR}/jxl/libjpegxl.pc.in" "libjpegxl.pc" @ONLY)