diff --git a/pkgs/development/lua-modules/overrides.nix b/pkgs/development/lua-modules/overrides.nix
index ef7b75482bec..932660230d7b 100644
--- a/pkgs/development/lua-modules/overrides.nix
+++ b/pkgs/development/lua-modules/overrides.nix
@@ -474,6 +474,13 @@ in
     buildInputs = old.buildInputs ++ [
       yajl
     ];
+    luarocksConfig = old.luarocksConfig // {
+      variables = {
+        # Since yajl's outputs are split, we need to help luarocks find the
+        # include directory.
+        YAJL_INCDIR = "${lib.getDev yajl}/include";
+      };
+    };
   });
 
   lua-zlib = prev.lua-zlib.overrideAttrs (old: {