Auto-engaging winch clutches, and associated systems and methods are disclosed. A representative winch can include a frame, a cable drum, a drive motor supported by the frame, a gear train, and an auto-engaging clutch mechanism. The gear train can include a ring gear and a gear set engaged with the ring gear, the drive motor, and the drum. The auto-engaging clutch mechanism can include a locking element movable from a disengaged position to an engaged position, wherein in the engaged position the ring gear is grounded to the frame, and the gear set is coupled to transfer torque between the drive motor and the cable drum. An engagement mechanism can be coupled between the locking element and the drive motor to automatically move the locking element from the disengaged position to the engaged position and to automatically decouple the locking element from the drive motor when the motor is rotated.