diff --git a/morph/lib/issuer-aws.nix b/morph/lib/issuer-aws.nix
index 8ff172803eda784898aba2d96636df1afcee36e5..80495e2dc7bafbc9bfbbe174e1a2f75f66942dfe 100644
--- a/morph/lib/issuer-aws.nix
+++ b/morph/lib/issuer-aws.nix
@@ -32,4 +32,8 @@
     dates = "weekly";
     options = "--delete-older-than 30d";
   };
+
+  # Turn on automatic optimization of nix store
+  # https://nixos.wiki/wiki/Storage_optimization
+  nix.autoOptimiseStore = true;
 }