Abstract: A bicycle trailer comprises a frame having at its one end a hitch assembly for connecting the bicycle trailer to a towing bicycle and at its other end a ground-engagable wheel. The hitch assembly comprises a clamp part for clamping non-rotatably to a seat supporting part, for example the seat post, of the towing bicycle, a universal joint portion fixedly attached to the trailer frame and a releasable fastening attaching the clamp part to the universal joint portion. The universal joint portion permits pivoting of the trailer, in use, about generally vertical and horizontal axes which are spaced apart, preferably with the second pivot axis between the first pivot axis and the trailer frame. The clamp part may comprise a generally U-shaped member having a cylindrical bight portion and a bolt member extending through aligned holes in end portions of the U-shaped member to urge them together and clamp the seat supporting part.