diff --git a/nixos/modules/services/networking/seafile.nix b/nixos/modules/services/networking/seafile.nix
index d9617952ea59f0..2eb3fbd3c39ede 100644
--- a/nixos/modules/services/networking/seafile.nix
+++ b/nixos/modules/services/networking/seafile.nix
@@ -27,6 +27,17 @@ let
     ${cfg.seahubExtraConf}
   '';
 
+  # Most official settings are irrelevant since seafdav is run via Gunicorn
+  # as WSGI application. Thus Gunicorn params are given inline.
+  # Only the share_name is actually consumed by seafdav itself. `enabled`
+  # is set simply to avoid confusion; seafdav doesn't act upon it.
+  seafdavConf = settingsFormat.generate "seafdav.conf" {
+    WEBDAV = {
+      enabled = cfg.webdav.enable;
+      share_name = cfg.webdav.shareName;
+    };
+  };
+
   seafRoot = "/var/lib/seafile"; # hardcode it due to dynamicuser
   ccnetDir = "${seafRoot}/ccnet";
   dataDir = "${seafRoot}/data";
@@ -137,6 +148,42 @@ in {
         for all available options.
       '';
     };
+
+    webdav = mkOption {
+      type = types.submodule {
+        options = {
+          enable = mkEnableOption "Seafile WebDAV Extension";
+          shareName = mkOption {
+            type = types.str;
+            default = "/";
+            example = "/webdav";
+            description = ''
+              Public path in URI under which the WebDAV server can be reached.
+            '';
+          };
+          workers = mkOption {
+            type = types.int;
+            default = 5;
+            example = 10;
+            description = ''
+              The number of gunicorn worker processes for handling requests.
+            '';
+          };
+          timeout = mkOption {
+            type = types.int;
+            default = 1200;
+            example = 920;
+            description = ''
+              Timeout for gunicorn in seconds. Affects large file uploads.
+            '';
+          };
+        };
+      };
+      default = { };
+      description = ''
+        Optional WebDAV extension.
+      '';
+    };
   };
 
   ###### Implementation
@@ -146,6 +193,7 @@ in {
     environment.etc."seafile/ccnet.conf".source = ccnetConf;
     environment.etc."seafile/seafile.conf".source = seafileConf;
     environment.etc."seafile/seahub_settings.py".source = seahubSettings;
+    environment.etc."seafile/seafdav.conf".source = seafdavConf;
 
     systemd.targets.seafile = {
       wantedBy = [ "multi-user.target" ];
@@ -292,6 +340,43 @@ in {
           fi
         '';
       };
+
+      seafdav = mkIf cfg.webdav.enable {
+        description = "Seafile WebDAV Extension";
+        wantedBy = [ "seafile.target" ];
+        partOf = [ "seafile.target" ];
+        after = [ "network.target" "seaf-server.service" ];
+        requires = [ "seaf-server.service" ];
+        restartTriggers = [ seahubSettings ];
+        environment = {
+          # needs /etc/seafile to access seahub_settings.py
+          PYTHONPATH = "${pkgs.seafdav.pythonPath}:${pkgs.seafdav}:/etc/seafile";
+          CCNET_CONF_DIR = ccnetDir;
+          SEAFILE_CONF_DIR = dataDir;
+          SEAFILE_CENTRAL_CONF_DIR = "/etc/seafile";
+          SEAFILE_RPC_PIPE_PATH = "/run/seafile";
+          SEAHUB_LOG_DIR = "/var/log/seafile";
+          SEAFDAV_CONF = "/etc/seafile/seafdav.conf";
+        };
+        serviceConfig = securityOptions // {
+          User = "seafile";
+          Group = "seafile";
+          DynamicUser = true;
+          RuntimeDirectory = "seafdav";
+          StateDirectory = "seafile";
+          LogsDirectory = "seafile";
+          ConfigurationDirectory = "seafile";
+          ExecStart = ''
+            ${pkgs.seafdav.python.pkgs.gunicorn}/bin/gunicorn seafdav:application \
+            --name seafdav \
+            --workers ${toString cfg.webdav.workers} \
+            --log-level=info \
+            --preload \
+            --timeout=${toString cfg.webdav.timeout} \
+            --bind unix:/run/seafdav/gunicorn.sock
+           '';
+        };
+      };
     };
   };
 }
diff --git a/nixos/tests/seafile.nix b/nixos/tests/seafile.nix
index 6eec8b1fbe55c8..c1fcea071e1589 100644
--- a/nixos/tests/seafile.nix
+++ b/nixos/tests/seafile.nix
@@ -16,6 +16,10 @@ import ./make-test-python.nix ({ pkgs, ... }:
           ccnetSettings.General.SERVICE_URL = "http://server";
           adminEmail = "admin@example.com";
           initialAdminPassword = "seafile_password";
+          webdav = {
+            enable = true;
+            shareName = "/webdav";
+          };
         };
         services.nginx = {
           enable = true;
@@ -33,6 +37,7 @@ import ./make-test-python.nix ({ pkgs, ... }:
                 proxy_http_version 1.1;
               '';
             };
+            locations."/webdav".proxyPass = "http://unix:/run/seafdav/gunicorn.sock:/webdav";
           };
         };
         networking.firewall = { allowedTCPPorts = [ 80 ]; };
@@ -117,5 +122,15 @@ import ./make-test-python.nix ({ pkgs, ... }:
           client2.succeed("ls -la test01 >&2")
 
           client2.succeed('[ `cat test01/first_file` = "bla" ]')
+
+      with subtest("start webdav-server"):
+          server.wait_for_unit("seafdav.service")
+          server.wait_for_file("/run/seafdav/gunicorn.sock")
+
+      with subtest("webdav download file"):
+          client2.succeed(
+            "curl http://server/webdav/test01/first_file -u admin\@example.com -p seafile_password -o first_file.webdav"
+          )
+          client2.succeed('[ `cat first_file.webdav` = "bla" ]')
     '';
   })