Abstract: A door drive for garage, garden, hall or factory doors, comprising a motor unit which comprises a drive motor and a motor output shaft, an output transmission, which on the input end can be connected with the motor output shaft and on the output end includes a transmission output shaft for driving a door moving element, in particular a door shaft, a release clutch for releasing the motor output shaft with respect to the door moving element as well as at least one damping element for damping drive shocks. The door drive is characterized in that the output transmission includes a transmission housing formed separate from the motor unit and together with the release clutch and the damping element forms a separate, modular drive attachment, which can be connected on the one hand to the motor unit and on the other hand to the door moving element.