The 2021 Boston Red Sox season was the 121st season in the team's history, and their 110th season at Fenway Park. The team entered the offseason conducting a managerial search, after declining to bring back Ron Roenicke from the shortened 2020 season. On November 6, 2020, the team re-hired Alex Cora as manager; Cora had skippered the Red Sox in 2018 and 2019, then sat out 2020 serving a one-year suspension for his role in the Houston Astros sign stealing scandal in 2017.

Jose Alexander Cora is a Puerto Rican baseball manager and former infielder who is the manager of the Boston Red Sox in Major League Baseball (MLB). He previously played in MLB for 14 seasons with the Red Sox, Los Angeles Dodgers, Cleveland Indians, New York Mets, Texas Rangers, and Washington Nationals. After retiring as a player, Cora served as the bench coach for the Houston Astros when they won their first World Series title in 2017. Cora was named Boston's manager the following season, winning a franchise-best 108 games and leading the team to victory in the 2018 World Series. He is the fifth MLB manager to win the World Series in his first season and the first Puerto Rican manager of a World Series-winning team.