Vivencio Baron Cuyugan, Sr. (January 13, 1895 – March 16, 1971) was a Filipino politician, boxer, and one of the founders of the socialist guerrilla group Hukbalahap. He was born in San Fernando, Pampanga, to Saturnino P. Cuyugan and Antonina Y. Baron. He studied in the United States where he supported himself through professional boxing and became known as the "Big Brown Filipino." He was appointed Municipal Vice-President of San Fernando in 1927, and later elected to the same position in 1931. He was later elected the first Municipal Mayor under the Philippine Commonwealth, the first socialist mayor of the Philippines. Together with Pedro Abad Santos, he was among the co-founders of the Socialist Party of the Philippines.