A guide system for guiding a window glass of a vehicle includes a guide rail and a guide. The guide includes a shaft to be attached to the window glass; a base as one part of a component divided in a widthwise direction of the vehicle and contacting an inner surface of the guide rail at an inner side of the vehicle; and a slider slidably attached to the base as the other part of the component and contacting an inner surface of the guide rail at an outer side of the vehicle. An elastic member is disposed between the base and the slider for pressing the slider toward the outside of the vehicle.