Leonard Robert Morrison Cocks OBE TD (born 17 June 1938) is a British geologist, formerly Keeper of Palaeontology, Natural History Museum.
Cocks was educated at Felstead School and Hertford College, Oxford.  After military service in Malaya he became a research student at Oxford, before joining the Natural History Museum in 1962. From 1970 to 1983 he served as a geologist with the Royal Engineers. He has served as president of the Geological Society, Palaeontological Association, Palaeontographical Society and Geologists' Association.
In 2010 he was awarded the Palaeontological Association's Lapworth Medal.