A drive system for rotating a wheel of an aircraft landing gear. The drive system has a drive pinion and a motor operable to rotate the drive pinion via a drive path. A rotary damper is provided in the drive path between the motor and the drive pinion. A driven gear is adapted to be attached to the wheel so as to be capable of rotating the wheel. The drive system has a drive configuration in which the drive pinion is capable of meshing with the driven gear to permit the motor to drive the driven gear via the drive path. One of the drive pinion and the driven gear comprises a roller gear having a series of rollers arranged to form a ring, each roller being rotatable about a roller axis, and the other of the drive pinion and the driven gear comprises a sprocket.