diff --git a/nixos/modules/services/monitoring/prometheus/exporters.nix b/nixos/modules/services/monitoring/prometheus/exporters.nix
index 258d13e3c7c7..0e92249ccba8 100644
--- a/nixos/modules/services/monitoring/prometheus/exporters.nix
+++ b/nixos/modules/services/monitoring/prometheus/exporters.nix
@@ -85,6 +85,7 @@ let
         "libvirt"
         "lnd"
         "mail"
+        "mailman3"
         "mikrotik"
         "modemmanager"
         "mongodb"
diff --git a/nixos/modules/services/monitoring/prometheus/exporters/mailman3.nix b/nixos/modules/services/monitoring/prometheus/exporters/mailman3.nix
new file mode 100644
index 000000000000..cbfede2bb9e2
--- /dev/null
+++ b/nixos/modules/services/monitoring/prometheus/exporters/mailman3.nix
@@ -0,0 +1,77 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+
+let
+  cfg = config.services.prometheus.exporters.mailman3;
+in
+{
+  port = 9934;
+  extraOpts = {
+    logLevel = lib.mkOption {
+      type = lib.types.enum [
+        "debug"
+        "info"
+        "warning"
+        "error"
+        "critical"
+      ];
+      default = "info";
+      description = ''
+        Detail level to log.
+      '';
+    };
+
+    mailman = {
+      addr = lib.mkOption {
+        type = lib.types.str;
+        default = "http://127.0.0.1:8001";
+        description = ''
+          Mailman3 Core REST API address.
+        '';
+      };
+
+      user = lib.mkOption {
+        type = lib.types.str;
+        default = "restadmin";
+        description = ''
+          Mailman3 Core REST API username.
+        '';
+      };
+
+      passFile = lib.mkOption {
+        type = lib.types.str;
+        default = config.services.mailman.restApiPassFile;
+        defaultText = lib.literalExpression "config.services.mailman.restApiPassFile";
+        description = ''
+          Mailman3 Core REST API password.
+        '';
+      };
+    };
+  };
+  serviceOpts = {
+    serviceConfig = {
+      LoadCredential = [
+        "password:${cfg.mailman.passFile}"
+      ];
+      ExecStart =
+        let
+          addr = "${
+            if (lib.hasInfix ":" cfg.listenAddress) then "[${cfg.listenAddress}]" else cfg.listenAddress
+          }:${toString cfg.port}";
+        in
+        ''
+          ${lib.getExe pkgs.prometheus-mailman3-exporter} \
+            --log-level ${cfg.logLevel} \
+            --web.listen ${addr} \
+            --mailman.address ${cfg.mailman.addr} \
+            --mailman.user ${cfg.mailman.user} \
+            --mailman.password-file %d/password \
+            ${lib.concatStringsSep " \\\n  " cfg.extraFlags}
+        '';
+    };
+  };
+}