Robert Lyell Mitchell FRSE FRSC (3 June 1910 – 7 February 1982) was a Scottish chemist and mountaineer.
He was born in Edinburgh on 3 June 1910 the son of David Hay Lyell Mitchell, an engineer based at Bangour Hospital.
He was educated at Bathgate Academy then studied science at the University of Edinburgh graduating with a BSc in 1931.
He undertook postgraduate studies in chemistry first at the University of Aberdeen gaining a PhD in 1934, and then the Technische Hochschule in Zürich in Switzerland, where he developed a passion for alpine climbing.
His proposers were Donald McArthur, Sir David Cuthbertson, Andrew Phillipson, Thomas Phemister, James Robert Matthews and Murray Macgregor.