diff --git a/modules/darwin/all/thunderbird.nix b/modules/darwin/all/thunderbird.nix
new file mode 100644
index 0000000..e0cff96
--- /dev/null
+++ b/modules/darwin/all/thunderbird.nix
@@ -0,0 +1,7 @@
+{
+  # https://github.com/nix-community/home-manager/issues/3407#issuecomment-1312712582
+  launchd.user.envVariables = {
+    MOZ_LEGACY_PROFILES = "1"; # thunderbird
+    MOZ_ALLOW_DOWNGRADE = "1"; # thunderbird
+  };
+}
diff --git a/modules/darwin/default.nix b/modules/darwin/default.nix
index eaccea1..d0603cf 100644
--- a/modules/darwin/default.nix
+++ b/modules/darwin/default.nix
@@ -16,5 +16,6 @@ in
     self.nixosModules.common
     inputs.ragenix.darwinModules.default
     ./all/zsh-completion-fix.nix
+    ./all/thunderbird.nix
   ];
 }
diff --git a/modules/home/all/email/default.nix b/modules/home/all/email/default.nix
index d8f810a..8521d92 100644
--- a/modules/home/all/email/default.nix
+++ b/modules/home/all/email/default.nix
@@ -15,6 +15,7 @@ in
 {
   imports = [
     ./himalaya.nix
+    ./thunderbird.nix
   ];
   accounts.email.accounts = {
     "srid@srid.ca" = iCloudMailSettings // {
diff --git a/modules/home/all/email/thunderbird.nix b/modules/home/all/email/thunderbird.nix
new file mode 100644
index 0000000..4ddc27d
--- /dev/null
+++ b/modules/home/all/email/thunderbird.nix
@@ -0,0 +1,22 @@
+{ pkgs, ... }:
+{
+  programs.thunderbird = {
+    enable = true;
+
+    # Thunderbird package is unavailable for Darwin.
+    # Install the app manually.
+    package = pkgs.hello;
+
+    profiles."default" = {
+      isDefault = true;
+    };
+  };
+
+  accounts.email.accounts = {
+    "srid@srid.ca" = {
+      thunderbird = {
+        enable = true;
+      };
+    };
+  };
+}