A bladeless fan assembly 1 comprising a nozzle 10 and means for creating an air flow through the nozzle 10. The nozzle comprises in interior passage 20 communicating with a mouth 12, which is arranged to direct airflow from the interior passage 20 over an adjacent surface 14, which may be convex. The nozzle 10 may be an annular, circumferentially continuous plenum, which may be at least 10cm in diameter and at least 5cm long. The nozzle 10 surface may comprise a diffuser which may be at least 5cm or 2/3 of the length of the nozzle 10, and may lie in a plane no more than 15 degrees from the horizontal. The mouth 12 may be at least part circular and the mouth opening may be less than 5mm. The air flow through the nozzle 10 may be created by a motor 30 and an impeller and there may be a duct communicating with the motor 30 and the nozzle 10.; The motor 30 may be a DC brushless motor with a mixed flow impeller. The fan 1 may be rotatable about its base 18 and may be mounted on the desk, floor, a wall or a ceiling; and it may include lighting, a clock, or an LCD.