diff --git a/extensions/gimp/README.md b/extensions/gimp/README.md
index d3dbae0..2aa18f0 100644
--- a/extensions/gimp/README.md
+++ b/extensions/gimp/README.md
@@ -16,6 +16,7 @@ You need GIMP 3 with its development files (`gimptool`).
 | Arch / Manjaro  | `sudo pacman -S gimp` (includes them)               |
 | Debian / Ubuntu | `sudo apt install libgimp-3.0-dev` (GIMP 3 packages) |
 | Fedora          | `sudo dnf install gimp-devel`                       |
+| NixOS           | `nix-shell gimp-shell.nix` (in this folder), then build inside that shell |
 | Windows         | MSYS2: `pacman -S mingw-w64-ucrt-x86_64-gimp`        |
 | macOS           | build GIMP 3 from source or use MacPorts/Homebrew   |
 
@@ -28,6 +29,11 @@ gimptool --install yapf-gimp.c
 That compiles the plugin (it pulls in `../../yapf.c` itself) and installs it
 into your personal GIMP plug-ins folder.  Restart GIMP.
 
+On NixOS, build with the same nixpkgs channel your GIMP comes from (the
+plugin links against that GIMP's libraries), and build it again after a
+GIMP update.  Your GIMP must be GIMP 3: `environment.systemPackages = [
+pkgs.gimp3 ];`, or `nix-shell -p gimp3 --run gimp` to try it.
+
 ### Manual build
 
 ```sh
diff --git a/extensions/gimp/gimp-shell.nix b/extensions/gimp/gimp-shell.nix
new file mode 100644
index 0000000..7a8fadf
--- /dev/null
+++ b/extensions/gimp/gimp-shell.nix
@@ -0,0 +1,7 @@
+# Development shell for building the plugin on NixOS: nix-shell gimp-shell.nix
+# `gimp3` is GIMP 3 on every channel (on unstable it is an alias of `gimp`).
+with import <nixpkgs> {};
+mkShell {
+  nativeBuildInputs = [ pkg-config ];
+  buildInputs = [ gimp3 gimp3.dev gtk3 glib gdk-pixbuf gegl babl cairo pango ];
+}