diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 735bcba..e54d8fb 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -4,9 +4,11 @@ on:
   push:
 jobs:
   build:
-    runs-on: ubuntu-latest
     strategy:
       matrix:
+        os:
+          - ubuntu-latest
+          - macos-11
         nix:
           - name: 2.4
             url: https://releases.nixos.org/nix/nix-2.4/install
@@ -14,6 +16,7 @@ jobs:
           #  url: https://releases.nixos.org/nix/nix-2.3.16/install
           #- name: 2.5pre
           #  url: https://github.com/numtide/nix-unstable-installer/releases/download/nix-2.5pre20211026_5667822/install
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2.3.5
       - uses: cachix/install-nix-action@v15
@@ -43,9 +46,10 @@ jobs:
         if: ${{ !contains(matrix.nix.name, '2.3') }}
 
   tests:
-    runs-on: ubuntu-latest
     strategy:
       matrix:
+        os:
+          - ubuntu-latest
         nix:
           - name: 2.3.16
             url: https://releases.nixos.org/nix/nix-2.3.16/install
@@ -53,6 +57,7 @@ jobs:
             url: https://releases.nixos.org/nix/nix-2.4/install
           - name: 2.5pre
             url: https://github.com/numtide/nix-unstable-installer/releases/download/nix-2.5pre20211026_5667822/install
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2.3.5
       - uses: cachix/install-nix-action@v15
diff --git a/default.nix b/default.nix
index b7ca333..eceddc2 100644
--- a/default.nix
+++ b/default.nix
@@ -41,6 +41,6 @@ in rustPlatform.buildRustPackage rec {
     homepage = "https://zhaofengli.github.io/colmena/${passthru.apiVersion}";
     license = licenses.mit;
     maintainers = with maintainers; [ zhaofengli ];
-    platforms = platforms.linux;
+    platforms = platforms.linux ++ platforms.darwin;
   };
 }
diff --git a/flake.nix b/flake.nix
index d18c82d..574296d 100644
--- a/flake.nix
+++ b/flake.nix
@@ -12,8 +12,7 @@
   };
 
   outputs = { self, nixpkgs, utils, ... }: let
-    # We aren't testing against Darwin at the moment
-    supportedSystems = [ "x86_64-linux" "i686-linux" "aarch64-linux" ];
+    supportedSystems = [ "x86_64-linux" "i686-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
   in utils.lib.eachSystem supportedSystems (system: let
     pkgs = import nixpkgs { inherit system; };
   in rec {