The partnership will allow MGM to use the NBA and WNBA brands on its casino games and sports betting platforms, and MGM will also have access to data from both leagues.
MGM will be promoted across the NBA's digital assets and social media platforms, and the NBA will be promoted across MGM's sports betting platforms.
MGM Resorts International Chairman and CEO Jim Murren said: "The NBA has always been an innovator at the forefront of sports evolution, and MGM Resorts is thrilled to partner with the league to revolutionise sports betting in the United States.
"Integrating the NBA's assets and having official NBA data showcased across the MGM Resorts platforms will provide us with a distinct advantage and instil more confidence in knowing that our data is directly from the NBA."
NBA Commissioner Adam Silver said: "As the landscape for sports betting in the US continues to evolve at a rapid pace, MGM Resorts is a proven gaming leader for us to work with on this groundbreaking partnership.
"Our collaboration will result in the best possible gaming and entertainment experience for consumers through the use of accurate, real-time NBA and WNBA data, and our collective efforts to maintain and enhance the integrity of our games."
ESPN has reported the deal will last three years, and is worth at least $25m.