Segundo Castillo Varela (17 July 1913 in Callao, Peru – 1 October 1993 in Callao, Peru) was a Peruvian footballer who played in Peru, Chile, Argentina and Colombia and for the Peru national football team. He was part of Peru's team at the 1936 Summer Olympics.
In addition to having played for Peru, he made an appearance for Chile in 1941.