End piece (8) configured for installation at a longitudinal extremity (7) of a windscreen wiper (1), the end piece (8) comprising an internal volume (13) and a peripheral wall (12) which delimits the internal volume (13), the end piece (8) comprising at least a first housing (14) configured to accommodate a heel (5a) of a wiper blade (5) and being in communication with a slot (19) which passes through the peripheral wall (12), the slot (19) being delimited by sides (18), the first housing (14) extending longitudinally from an inlet (21), through which the heel (5a) of the wiper blade (5) may be introduced into the first housing (14), and extending preferably as far as a bottom wall (12a) of the peripheral wall (12), the first housing (14) being delimited by a longitudinal wall (17) disposed in the internal volume (13), characterized in that a first distance D1 measured at the inlet (21) between one of the sides (18) delimiting the slot (19) and the longitudinal wall (17) is greater than a second distance D2 separate from the first distance D1 and measured parallel to the first distance D1, the second distance D2 being measured between one of the sides (18) of the slot (19) and the longitudinal wall (17).