--- a/cmake/QtBuildPathsHelpers.cmake
+++ b/cmake/QtBuildPathsHelpers.cmake
@@ -140,7 +140,7 @@ function(qt_configure_process_path name default docstring)
         set(new_value ".")
     elseif(rel_path MATCHES "^\.\./")
         # INSTALL_SYSCONFDIR is allowed to be outside the prefix.
-        if(NOT name STREQUAL "INSTALL_SYSCONFDIR")
+        if(NOT (name STREQUAL "INSTALL_SYSCONFDIR" OR name STREQUAL "INSTALL_TRANSLATIONSDIR"))
             message(FATAL_ERROR
                 "Path component '${name}' is outside computed install prefix: ${rel_path} ")
         endif()