Don Upatissa Gamanayake alias Dias Mudalali (17 October 1948–13 November 1989: Sinhala: උපතිස්ස ගමනායක), was a Sri Lankan politician and the deputy leader of the Jantha Vimukthi Peramuna (JVP) during the 1987–89 insurrection. Not a prominent figure during the JVP's 1971 insurrection, Gamanayake emerged as a leader only after the releasing of the JVP detainees in 1977. He moved up rapidly in the party hierarchy during the JVP's 1977-83 democratic phase and became the second in command after the founder and the leader, Rohana Wijeweera. He unsuccessfully contested the 1983 Anamaduwa by-election under JVP. Gamanayake was captured and killed by the government forces in November 1989.