Alejo Mancisidor (born 31 July 1970) is a former professional tennis player from Spain.

[1] Mancisidor played NCAA tennis while at Pepperdine University and was an All-American.

[2] He was a quarter-finalist at the Guarujá Open in 1992, with wins over Peru's Jaime Yzaga and German Marc-Kevin Goellner.

[3] He defeated Yzaga again in 1994, at the Bancolombia Open, when the Peruvian was ranked 19th in the world.

[3] Mancisidor coached WTA top 10 player Garbiñe Muguruza between 2010 and 2015.