Derwent Lees (14 November 1884 – 24 March 1931) was an Australian landscape painter.
Derwent Lees was born Desmond Lees in Hobart, Australia, in 1884. He lost a foot in a riding accident as a youth, while studying at Melbourne Grammar School in 1899-1900. Moving to London in 1905, Lees studied at the Slade School of Fine Art, joining its staff in 1908. He was a member of the New English Art Club from 1911. The earliest known pencil work of a model is from 1909 while at the Slade school and is held in a private collection in Doreen, Victoria, Australia.
He was a friend of Augustus John and James Dickson Innes, and spent the period from late 1910 to 1912 with them at a cottage called Nant Ddu in north Wales. In 1912 Innes and Lees went on another painting trip to Collioure in France. His wife Lyndra was one of Augustus John's former models. He was the only Australian artist represented at the 1913 Armory Show in New York.
His artistic career was curtailed by a mental health problem which saw him confined to an asylum from 1918 until his death in 1931.