A resettable training device and method for training a user on the operation of an auto-injector for dispensing a medicament are provided. The user can operate the training device to simulate an auto-injector operation and then reset the training device to repeat the injector operation. The training device includes a housing, a cover member slidably received within the housing between a retracted operative position and an extended inoperative position, a spring member for biasing the cover member into the extended position, an actuation assembly that controls the movement of the cover member from the retracted position to the extended position in response to activation of the trainer by the user, a safety pin, and in some embodiments at least one releasable locking assembly to prevent movement of the cover member from the extended position to the retracted position.