An on-board toilet cubicle for an aircraft, including a front long side and a rear long side; a front short side and a rear short side, which are each connected at one end to the front long side and at their other end to the rear long side, the long sides and the short sides enclosing an interior of the toilet cubicle, and the front and the rear long sides each being wider than the front and the rear short sides; a toilet unit with a toilet opening; and an L-shaped door for accessing the on-board toilet cubicle, the L-shaped door having one door leg in the front long side and one door leg in the front short side, the toilet unit arranged adjacent to the rear long side, and the door leg in the front long side being wider than the door leg in the front short side.