Reginald Southey (15 September 1835 – 8 November 1899) was an English physician and inventor of Southey's cannula or tube, a type of trocar used for draining oedema of the limbs.
Southey was a nephew of Romantic poet Robert Southey, and the fifth son of medical doctor Henry Herbert Southey. A graduate of Christ Church, Oxford, he studied medicine at St Bartholomew's Hospital before travelling the world. He went on to serve as a member of the Lunacy Commission from 1883 until 1898. He was Gulstonian Lecturer in 1867.
He was a lifelong friend of Charles Lutwidge Dodgson ('Lewis Carroll'), and encouraged Dodgson to take up photography.