This application provides an off-board charger, a charging system, and a charging station. The off-board charger includes a power conversion circuit, a power supply port, a conversion adapter, and a controller. The conversion adapter includes a connection port and an alternating current output port. The controller controls, when the conversion adapter is connected to the power supply port, the power supply port to connect to an alternating current power grid, the power supply port to connect to the connection port, and the alternating current output port to connect to a charging port of a powered device; or controls, when the conversion adapter is disconnected from the power supply port, the power conversion circuit to connect to an alternating current power grid, and the power supply port to connect to the charging port of the powered device. The off-board charger provided in this application implements both alternating current charging and direct current charging. This omits a charging gun cable and reduces costs.