This announcement comes ahead of Massachusetts's plans to launch legalised online sports betting on March 10.
BetMGM is one of the seven operators ready to launch their respective sportsbooks on March 10.
Matt Prevost, Chief Revenue Officer, BetMGM, said: "The Red Sox are one of baseball's most beloved organizations and we're thrilled to bring BetMGM to their passionate fans.
“We look forward to working together to elevate the gameday experience in Boston."
As part of the deal, BetMGM will have branded advertising at Fenway Park, the home stadium of the Boston Red Sox. The signs will be featured on the Green Monster that makes up the left field wall and inside a suite that will be used to host VIP fan experiences.
Co-branded content will also be hosted across the digital and social platforms of both BetMGM and Boston Red Sox.
Troup Parkinson, EVP, Partnerships, Boston Red Sox, said: “The Boston Red Sox are proud to partner with BetMGM as we prepare to enter a new era of professional sports betting in Massachusetts.
“Given our strong relationship with MGM Resorts, BetMGM was the clear choice to become the first sports betting partner of the club, and we look forward to them offering sports betting opportunities to our fans in a safe and responsible manner."
MGM Resorts, joint owner of BetMGM with Entain, already has a multi-year partnership, which makes it the Official Resort Casino of the Boston Red Sox.
