| Segundo Castillo | |
| Fullname: | Segundo Castillo Varela |
| Birth Date: | 17 July 1913 |
| Birth Place: | Callao, Peru |
| Death Place: | Callao, Peru |
| Position: | Central Midfielder |
| Years1: | 1932 |
| Clubs1: | Unión Buenos Aires |
| Years2: | 1933–1939 |
| Clubs2: | Sport Boys |
| Years3: | 1939–1940 |
| Clubs3: | Lanús |
| Years4: | 1941–1942 |
| Clubs4: | Magallanes |
| Years5: | 1943–1947 |
| Clubs5: | Deportivo Municipal |
| Years6: | 1948–1949 |
| Clubs6: | Universitario |
| Years7: | 1950 |
| Clubs7: | Independiente Medellín |
| Years8: | 1951–1952 |
| Clubs8: | Universitario |
| Years9: | 1953–1954 |
| Clubs9: | Unión Callao |
| Nationalyears1: | 1936–1939 |
| Nationalteam1: | Peru |
| Nationalcaps1: | 11 |
| Nationalgoals1: | 0 |
| Nationalyears2: | 1941 |
| Nationalteam2: | Chile |
| Nationalcaps2: | 1 |
| Nationalgoals2: | 0 |
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.[1]
In addition to having played for Peru, he made an appearance for Chile in 1941.[2]