The invention provides apparatus (6) for moving a trailer. The apparatus has at least one drive unit (8) a drive unit mounting (16) and an actuation means (36) associated with the, or each, drive unit (8). The, or each, drive unit (8) includes a roller (12) for frictionally engaging a wheel (4) of a trailer and a motor (14) for driving the roller. The drive unit mounting (6) is suitable for securing the drive unit (8) to a trailer, the, or each, drive unit (8) is movably coupled to the drive unit mounting (6). The, or each, actuation means (36) is coupled to the drive unit mounting (16) such that, when actuated, the actuation means (36) causes the roller (12) with which it is associated to move relative to the drive unit mounting (6) along a translational axis so that, in use, the actuation means (36) can be actuated to move the roller (12) between an engaged position, in which the roller (12) is engaged with the wheel (4) of a trailer, and a released position, in which the roller (12) is not engaged with the wheel (4) of a trailer. The or each drive unit (8) comprises a gear arrangement (46,48) including an actuation means (36) arranged for rotational movement about an axis of rotation which is non-parallel and non-collinear with the translational axis, wherein rotational movement of the actuation means (36) causes the roller (12) to move relative to the drive unit mounting (16).