Robert Morton Nance (1873–1959) was a leading authority on the Cornish language, nautical archaeologist, and joint founder of the Old Cornwall Society.
Nance was born in Cardiff to Cornish parents. He wrote many books and pamphlets on the Cornish language, including a Cornish dictionary, which is a standard work, and edited magazines and pamphlets about Cornwall, including Old Cornwall, the journal of the Federation of Old Cornwall Societies. Nance was also a nautical archaeologist of distinction and was an originator of the Society for Nautical Research. His insight and learning were displayed in his book Sailing-ship Models which appeared in 1924. He studied art in Britain and France and was both a painter and a skilled craftsman.