M will work closely with the UK Government and the North Atlantic Treaty Organisation (NATO) to design, plan and implement logistics for the event.
Sean Buckley, director of M, said: "To be entrusted with such a prestigious global event is an enormous responsibility, as well as a great honour. There will be government ministers, representatives from international bodies and heads of state from more than 60 countries.
"We are expecting almost 2,500 delegates that will need to be accommodated in a suite of meeting rooms. The world's press will also be present and previous events have attracted up to 1,500 accredited media.
"As you would expect, the NATO summit will put the UK on a world stage so our job is to perpetuate this country's impeccable reputation for hosting world events."