Don Philip Rupasinghe Gunawardena (11 January 1901 – 26 March 1972) was a Sri Lankan Marxist politician and leftist. A founder of the Lanka Sama Samaja Party, the first political party in Ceylon which was known for having introduced Trotskyism, he later formed the Mahajana Eksath Peramuna and was called 'the Father of Socialism' and as 'the Lion of Boralugoda'. A member of the State Council of Ceylon and the Parliament of Ceylon, he served as the Minister of Agriculture and food under S. W. R. D. Bandaranaike from 1956 to 1959 and as Minister of Industries and Fisheries in the national government under Dudley Senanayake from 1965 to 1970.