diff --git a/build/cmake/contrib/gen_html/CMakeLists.txt b/build/cmake/contrib/gen_html/CMakeLists.txt
index 958e9d173..c4062d475 100644
--- a/build/cmake/contrib/gen_html/CMakeLists.txt
+++ b/build/cmake/contrib/gen_html/CMakeLists.txt
@@ -27,4 +27,4 @@ ADD_CUSTOM_TARGET(zstd_manual.html ALL
                   ${GENHTML_BINARY} "${LIBVERSION}" "${LIBRARY_DIR}/zstd.h" "${PROJECT_BINARY_DIR}/zstd_manual.html"
                   DEPENDS gen_html COMMENT "Update zstd manual")
 
-INSTALL(FILES "${PROJECT_BINARY_DIR}/zstd_manual.html" DESTINATION "${CMAKE_INSTALL_PREFIX}/${DOC_INSTALL_DIR}")
+INSTALL(FILES "${PROJECT_BINARY_DIR}/zstd_manual.html" DESTINATION "${CMAKE_INSTALL_DOCDIR}")