diff --git a/.circleci/config.yml b/.circleci/config.yml
index f99460b7cb8c72a1ffb6b7c74208ac37057b45fe..128b35641a11b3c5c6743d2dbaa0dc9daf3cf621 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -143,6 +143,10 @@ jobs:
       # Run in a highly Nix-capable environment.
       - image: "nixos/nix:latest"
 
+    # Tahoe-LAFS requires more memory than we get from the default resource
+    # class and sometimes we have to build it.
+    resource_class: "large"
+
     environment:
       # CACHIX_AUTH_TOKEN is manually set in the CircleCI web UI and allows us to push to CACHIX_NAME.
       CACHIX_NAME: "privatestorage-opensource"