The network rollout will begin later this year. It will provide spectators with fast, reliable Wi-Fi connectivity and improve the club's delivery of digital services.
Manchester United will also benefit from access real-time network analytics that will be used to make decisions affecting the fan experience and venue operations more generally.
For example, it will help identify bottlenecks around the stadium, overcrowded concessions and other consumer traffic patterns, and insights into fan activity will be used to better customise experiences and pinpoint sponsorship opportunities.
"Our collaboration with Extreme Networks is an important step in our drive to enhance and modernise the in-stadium fan experience at Old Trafford, opening up exciting opportunities for the Club to deliver next-generation digital services to fans on matchdays and to visitors throughout the year," said Manchester United chief operating officer Collette Roche.
"Old Trafford is known as The Theatre of Dreams because of its 112-year history of triumphs and dramas. With experience working with other iconic venues around the world, Extreme will help us keep our stadium up to date while preserving the character that makes it unique. Providing fast, reliable Wi-Fi to fans, underpinned by cutting-edge analytics to optimise performance, is a crucial part of that process."
Extreme Networks president and CEO Ed Meyercord said "Speed, precision and performance are equally important on and off the pitch, and Manchester United is investing to make the stadium experience just as impressive as the match itself.
"We're thrilled to partner with one of the world's most celebrated sports clubs to provide the technical DNA that will forever change the way fans experience Old Trafford. We believe the combination of Extreme's Wi-Fi 6 and analytics will provide the insights and scale required to ensure success and that fans won't miss a beat."