Janet's Foss is a small waterfall in the vicinity of the village of Malham, North Yorkshire. It carries Gordale Beck over a limestone outcrop topped by tufa into a deep pool below. The pool was traditionally used for sheep dipping, an event which took on a carnival air and drew the village inhabitants for the social occasion. The name Janet (sometimes Jennet) is believed to refer to a fairy queen held to inhabit a cave at the rear of the fall. Foss is a Nordic word for waterfall, still used in Scandinavia, and is presented in a number of cases in England as 'force'.
Janet's Foss was the location of the fictional Molkham Falls as featured in the 2006 independent British film, WATERFALL. Filming took place there in May 2006.