A bi-fold door stop controls movement and travel of lead and pivot doors in a set of vertically hung bi-fold doors. The bi-fold door stop has at least two non-parallel surfaces that each may act upon one or both of the lead and pivot door stiles to limit movement in two directions. Movement transverse to the track longitudinal axis is limited when the bi-fold door is either fully open or fully closed, while parallel movement is controlled by limiting the extent that the bi-fold door may be opened. At least two non-parallel surfaces are provided that each may act upon one or more of the lead and pivot door stiles, while an additional surface may act upon the face of the pivot door. The bi-fold door stop may be fabricated as a single part using common molding operations, and acts directly on the door panels, thereby preserving bi-fold door hardware.