Ralph Lainson (21 February 1927 – 5 May 2015) was a British parasitologist who studied leishmaniasis in Brazil.

His father, Charles Harry Lainson was a chemist for Portland Cement and his mother was Annie May née Denyer.

In 1969, Lainson recorded Chagas' disease for the first time, and in 1979, he proposed a classification system for different leishmania species.

[4] He was elected a Fellow of the Royal Society in 1982[5][6] and awarded the OBE in the 1996 Birthday Honours.

[1] Lainson married twice, on 28 September 1957 to Ann Patricia Russell (they had three children together) and then in 1974 to Zeá Constante Lins.