An image forming apparatus includes an apparatus main body, a process cartridge, a scanner unit, and a toner cartridge. The process cartridge is detachably mounted on the apparatus main body. The process cartridge includes: a photosensitive drum configured to rotate about a rotational axis extending in a first direction; and a development unit configured to supply toner to the photosensitive drum. The toner cartridge is configured to store toner. At least part of the photosensitive drum, at least part of the scanner unit, and at least part of the toner cartridge are aligned in a second direction in this order. The second direction is perpendicular to both the first direction and to a vertical direction. The at least part of the photosensitive drum, the at least part of the scanner unit, and the at least part of the toner cartridge overlap one another as viewed from the second direction.