A post-processing apparatus includes a post-processing device, an ejection device, and an ejection tray. The post-processing device executes post-processing on a medium on which an image is formed by an image forming apparatus. The ejection device ejects the medium on which the post-processing is executed by the post-processing device. The ejection tray holds the medium ejected by the ejection device. The ejection tray includes a main tray having an upper face inclined downward in an ejection direction, and a movable tray being rotatably supported by the main tray between a stacking position at which the medium ejected by the ejection device remains stacked on the upper face of the main tray and an ejection position at which the medium ejected by the ejection device slides along the upper face of the main tray.