diff --git a/modules/nvim.nix b/modules/nvim.nix
index 1fbdaa0..391fbc4 100644
--- a/modules/nvim.nix
+++ b/modules/nvim.nix
@@ -248,6 +248,17 @@ in
         };
       };
 
+      # Moodle/Mustache templates. nvim detects `.mustache` as filetype mustache
+      # but ships no syntax file for it, so the buffer renders as plain text.
+      # Tree-sitter is not an option here: the Handlebars grammar (glimmer)
+      # rejects mustache's argument-less sections, `{{{unescaped}}}`, partials
+      # and Moodle's `{{< parent }}` inheritance, and a single error node drops
+      # highlighting for the rest of the file. This plugin carries the syntax,
+      # indent and ftdetect scripts. nixpkgs marks it unfree only because
+      # upstream ships no license metadata; `allowUnfree` in modules/nixos.nix
+      # already covers it.
+      extraPlugins = [ pkgs.vimPlugins.vim-mustache-handlebars ];
+
       # Global (non-LSP) keymaps. Deliberately small — a starting point to grow.
       keymaps = [
         { mode = "n"; key = "<leader>w"; action = "<cmd>w<cr>"; options.desc = "Save"; }