diff --git a/nixos/doc/manual/release-notes/rl-2505.section.md b/nixos/doc/manual/release-notes/rl-2505.section.md
index 453e0ed450bd..d4576463ed1e 100644
--- a/nixos/doc/manual/release-notes/rl-2505.section.md
+++ b/nixos/doc/manual/release-notes/rl-2505.section.md
@@ -62,6 +62,8 @@
 
 - [vwifi](https://github.com/Raizo62/vwifi), a Wi-Fi simulator daemon leveraging the `mac80211_hwsim` and `vhost_vsock` kernel modules for efficient simulation of multi-node Wi-Fi networks. Available as {option}`services.vwifi`.
 
+- [Oncall](https://oncall.tools), a web-based calendar tool designed for scheduling and managing on-call shifts. Available as [services.oncall](options.html#opt-services.oncall).
+
 - [Homer](https://homer-demo.netlify.app/), a very simple static homepage for your server. Available as [services.homer](options.html#opt-services.homer).
 
 - [Ghidra](https://ghidra-sre.org/), a software reverse engineering (SRE) suite of tools. Available as [programs.ghidra](options.html#opt-programs.ghidra).
diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index 073f8ebede1a..d4f09fef8364 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -1608,6 +1608,7 @@
   ./services/web-apps/nostr-rs-relay.nix
   ./services/web-apps/ocis.nix
   ./services/web-apps/olivetin.nix
+  ./services/web-apps/oncall.nix
   ./services/web-apps/onlyoffice.nix
   ./services/web-apps/open-web-calendar.nix
   ./services/web-apps/openvscode-server.nix
diff --git a/nixos/modules/services/web-apps/oncall.nix b/nixos/modules/services/web-apps/oncall.nix
new file mode 100644
index 000000000000..cd842606f278
--- /dev/null
+++ b/nixos/modules/services/web-apps/oncall.nix
@@ -0,0 +1,203 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+
+  cfg = config.services.oncall;
+  settingsFormat = pkgs.formats.yaml { };
+  configFile = settingsFormat.generate "oncall_extra_settings.yaml" cfg.settings;
+
+in
+{
+  options.services.oncall = {
+
+    enable = lib.mkEnableOption "Oncall web app";
+
+    package = lib.mkPackageOption pkgs "oncall" { };
+
+    database.createLocally = lib.mkEnableOption "Create the database and database user locally." // {
+      default = true;
+    };
+
+    settings = lib.mkOption {
+      type = lib.types.submodule {
+        freeformType = settingsFormat.type;
+        options = {
+          oncall_host = lib.mkOption {
+            type = lib.types.str;
+            default = "localhost";
+            description = "FQDN for the Oncall instance.";
+          };
+          db.conn = {
+            kwargs = {
+              user = lib.mkOption {
+                type = lib.types.str;
+                default = "oncall";
+                description = "Database user.";
+              };
+              host = lib.mkOption {
+                type = lib.types.str;
+                default = "localhost";
+                description = "Database host.";
+              };
+              database = lib.mkOption {
+                type = lib.types.str;
+                default = "oncall";
+                description = "Database name.";
+              };
+            };
+            str = lib.mkOption {
+              type = lib.types.str;
+              default = "%(scheme)s://%(user)s@%(host)s:%(port)s/%(database)s?charset=%(charset)s&unix_socket=/run/mysqld/mysqld.sock";
+              description = ''
+                Database connection scheme. The default specifies the
+                connection through a local socket.
+              '';
+            };
+            require_auth = lib.mkOption {
+              type = lib.types.bool;
+              default = true;
+              description = ''
+                Whether authentication is required to access the web app.
+              '';
+            };
+          };
+        };
+      };
+      default = { };
+      description = ''
+        Extra configuration options to append or override.
+        For available and default option values see
+        [upstream configuration file](https://github.com/linkedin/oncall/blob/master/configs/config.yaml)
+        and the administration part in the
+        [offical documentation](https://oncall.tools/docs/admin_guide.html).
+      '';
+    };
+
+    secretFile = lib.mkOption {
+      type = lib.types.pathWith {
+        inStore = false;
+        absolute = true;
+      };
+      example = "/run/keys/oncall-dbpassword";
+      description = ''
+        A YAML file containing secrets such as database or user passwords.
+        Some variables that can be considered secrets are:
+
+        - db.conn.kwargs.password:
+          Password used to authenticate to the database.
+
+        - session.encrypt_key:
+          Key for encrypting/signing session cookies.
+          Change to random long values in production.
+
+        - session.sign_key:
+          Key for encrypting/signing session cookies.
+          Change to random long values in production.
+      '';
+    };
+
+  };
+
+  config = lib.mkIf cfg.enable {
+
+    # Disable debug, only needed for development
+    services.oncall.settings = lib.mkMerge [
+      ({
+        debug = lib.mkDefault false;
+        auth.debug = lib.mkDefault false;
+      })
+    ];
+
+    services.uwsgi = {
+      enable = true;
+      plugins = [ "python3" ];
+      user = "oncall";
+      instance = {
+        type = "emperor";
+        vassals = {
+          oncall = {
+            type = "normal";
+            env = [
+              "PYTHONPATH=${pkgs.oncall.pythonPath}"
+              (
+                "ONCALL_EXTRA_CONFIG="
+                + (lib.concatStringsSep "," (
+                  [ configFile ] ++ lib.optional (cfg.secretFile != null) cfg.secretFile
+                ))
+              )
+              "STATIC_ROOT=/var/lib/oncall"
+            ];
+            module = "oncall.app:get_wsgi_app()";
+            socket = "${config.services.uwsgi.runDir}/oncall.sock";
+            socketGroup = "nginx";
+            immediate-gid = "nginx";
+            chmod-socket = "770";
+            pyargv = "${pkgs.oncall}/share/configs/config.yaml";
+            buffer-size = 32768;
+          };
+        };
+      };
+    };
+
+    services.nginx = {
+      enable = lib.mkDefault true;
+      virtualHosts."${cfg.settings.oncall_host}".locations = {
+        "/".extraConfig = "uwsgi_pass unix://${config.services.uwsgi.runDir}/oncall.sock;";
+      };
+    };
+
+    services.mysql = lib.mkIf cfg.database.createLocally {
+      enable = true;
+      package = lib.mkDefault pkgs.mariadb;
+      ensureDatabases = [ cfg.settings.db.conn.kwargs.database ];
+      ensureUsers = [
+        {
+          name = cfg.settings.db.conn.kwargs.user;
+          ensurePermissions = {
+            "${cfg.settings.db.conn.kwargs.database}.*" = "ALL PRIVILEGES";
+          };
+        }
+      ];
+    };
+
+    users.users.oncall = {
+      group = "nginx";
+      isSystemUser = true;
+    };
+
+    systemd = {
+      services = {
+        uwsgi.serviceConfig.StateDirectory = "oncall";
+        oncall-setup-database = lib.mkIf cfg.database.createLocally {
+          description = "Set up Oncall database";
+          serviceConfig = {
+            Type = "oneshot";
+            RemainAfterExit = true;
+          };
+          requiredBy = [ "uwsgi.service" ];
+          after = [ "mysql.service" ];
+          script =
+            let
+              mysql = "${lib.getExe' config.services.mysql.package "mysql"}";
+            in
+            ''
+              if [ ! -f /var/lib/oncall/.dbexists ]; then
+                # Load database schema provided with package
+                ${mysql} ${cfg.settings.db.conn.kwargs.database} < ${cfg.package}/share/db/schema.v0.sql
+                ${mysql} ${cfg.settings.db.conn.kwargs.database} < ${cfg.package}/share/db/schema-update.v0-1602184489.sql
+                touch /var/lib/oncall/.dbexists
+              fi
+            '';
+        };
+      };
+    };
+
+  };
+
+  meta.maintainers = with lib.maintainers; [ onny ];
+
+}