Mynydd y Glyn is a mountain in South Wales, between the towns of Pontypridd and Tonyrefail. It has a height above sea level of 377 metres.
It is the mountain which was used in The Englishman who went up a Hill and came down a Mountain in which Hugh Grant and Ian McNeice star as English cartographers. In the film the mountain is known as 'Ffynnon Garw'. It is a UK listed Marilyn.