diff --git a/.circleci/config.yml b/.circleci/config.yml
index befb9893f8854f7eb4ea2c6caf92f27f3b084f0e..6f6987cf85d04d37efe0e22d472964b7ee4b5174 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -29,7 +29,7 @@ jobs:
       # time of this comment.  We can bump it to a newer version when that
       # makes sense.  Meanwhile, the platform won't shift around beneath us
       # unexpectedly.
-      NIXPKGS_REV: "5de44c15758465f8ddf84d541ba300b48e56eda4"
+      NIXPKGS_REV: "92609f3d9bc3acffbdbe54fa1c591a885612aa73"
 
     steps:
       - run:
diff --git a/nix/sources.json b/nix/sources.json
index 52ce25c38c788e4a595b6eade67fe66c2f75d9f7..fc5bbbbb6468aed32a38328e7577a4fd2a54c2a9 100644
--- a/nix/sources.json
+++ b/nix/sources.json
@@ -24,15 +24,15 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs": {
-        "branch": "release-20.03",
+        "branch": "release-21.05",
         "description": "Nix Packages collection",
         "homepage": "",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "246b75a0d0d7da135a3e62c686b98975c30df42c",
-        "sha256": "0px8k4lh5nhq6f7pxqw8yawl5494njv22z4rmssywqkanf1xjs32",
+        "rev": "92609f3d9bc3acffbdbe54fa1c591a885612aa73",
+        "sha256": "09n9j2lr8632xrslpwsk4222xcq7h1f7lj0vjc2b90v3c64hqwml",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/246b75a0d0d7da135a3e62c686b98975c30df42c.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/92609f3d9bc3acffbdbe54fa1c591a885612aa73.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     }
 }