McJoe Arroyo (born December 5, 1985) is a Puerto Rican amateur boxer best known for winning a bronze medal at the 2007 World Amateur Boxing Championships as a bantamweight.
His twin brother McWilliams Arroyo is also a boxer and qualified for the 2008 Olympic Games. Both of the Arroyo brothers won a medal at the World Amateur Boxing Championships, being the only pair of twins to win medals in this competition. They were also the second twins to qualify for the Olympics in boxing.
McJoe was born along his twin brother, McWilliams, in the municipality of Ceiba in the northeast coastal region of Puerto Rico's main island. Arroyo and his twin, were introduced to boxing in their childhood. At the age of 12, they entered Gimnasio Fito Ramos, a gymnasium located in the municipality of Fajardo, Puerto Rico. In this locale they met Anthony Otero, a retired amateur boxer, who became their trainer during this stage of their careers. They initially took up the sport as a hobby, but after six fights they began establishing a pattern of only spending a limited amount of time inactive during a month, visiting the gymnasium at least every two weeks.