Abstract: A seat belt buckle, in particular for racing vehicles, has a casing with four connection points for connecting respective branches of a seat belt; three of the connection points are defined by two top slots and one bottom slot having respective inlets formed in a peripheral surface of the casing; the casing houses a coupling mechanism for retaining respective tabs inside the slots, and supports a lever having a radial arm, which is located on a bottom portion of the casing and is rotatable manually about an axis to release the coupling mechanism; the bottom slot is aligned, in a direction parallel to the rotation axis of the lever, with the rest position of the lever; and the fourth connection point is defined by an opening located alongside the bottom portion, on the opposite side to the inlet of the bottom slot.