Mon Rivera is the common name given to two distinct Puerto Rican musicians, namely Monserrate Rivera Alers and his oldest son, Efraín Rivera Castillo.
Efraín was specifically known for salsa and a Puerto Rican style called plena. He is credited for a fast humorous style and for introducing the sound of an all-trombone brass section to Afro-Rican orchestra music.
Three of Efraín's brothers were also musicians. Efraín's son is the percussionist, Javier Rivera.