A parking assist system includes an electronic control unit (14). The electronic control unit (14) is configured to set at least one candidate position (C) that is a candidate for a target position of a moving path of a vehicle (1) on the basis of at least one of a detected obstacle (B) or a detected parking boundary (D), rank each of the at least one candidate position (C) on the basis of the candidate position (C) and a position and orientation of the host vehicle, and determine one of the ranked at least one candidate position (C) as the target position.