diff --git a/pkgs/servers/x11/xorg/overrides.nix b/pkgs/servers/x11/xorg/overrides.nix
index 997552e5e259..2fbe9162a3a2 100644
--- a/pkgs/servers/x11/xorg/overrides.nix
+++ b/pkgs/servers/x11/xorg/overrides.nix
@@ -49,6 +49,11 @@ in
 
   libX11 = attrs: attrs // {
     preConfigure = setMalloc0ReturnsNullCrossCompiling;
+    postInstall =
+      ''
+        # Remove useless DocBook XML files.
+        rm -rf $out/share/doc
+      '';
   };
 
   libXrender = attrs: attrs // {