diff --git a/Library/Homebrew/extend/os/linux/diagnostic.rb b/Library/Homebrew/extend/os/linux/diagnostic.rb
index fea32b3893e02..234808224e24f 100644
--- a/Library/Homebrew/extend/os/linux/diagnostic.rb
+++ b/Library/Homebrew/extend/os/linux/diagnostic.rb
@@ -60,8 +60,8 @@ def check_tmpdir_executable
       end
 
       def check_xdg_data_dirs
-        xdg_data_dirs = ENV.fetch("XDG_DATA_DIRS", nil)
-        return if xdg_data_dirs.blank? || xdg_data_dirs.split("/").include?(HOMEBREW_PREFIX/"share")
+        xdg_data_dirs = ENV.fetch("HOMEBREW_XDG_DATA_DIRS", nil)
+        return if xdg_data_dirs.blank? || xdg_data_dirs.split(":").include?(HOMEBREW_PREFIX/"share")
 
         <<~EOS
           Homebrew's share was not found in your XDG_DATA_DIRS but you have
diff --git a/bin/brew b/bin/brew
index 706c6c615b378..a4b06170b70c6 100755
--- a/bin/brew
+++ b/bin/brew
@@ -185,6 +185,7 @@ USED_BY_HOMEBREW_VARS=(
   SUDO_USER
   TMUX
   XDG_CACHE_HOME
+  XDG_DATA_DIRS
   XDG_RUNTIME_DIR
   ZDOTDIR
 )