diff --git a/modules/gc.nix b/modules/gc.nix
index 790d589..2b0c621 100644
--- a/modules/gc.nix
+++ b/modules/gc.nix
@@ -1 +1,13 @@
-# TODO: Define garbage collection settings.
+{ ... }:
+
+{
+  nix.gc = {
+    automatic = true;
+    dates = "weekly";
+    options = "--delete-older-than 14d";
+  };
+
+  nix.optimise.automatic = true;
+
+  boot.tmp.cleanOnBoot = true;
+}