The former England captain had been included on coach Stuart Pearce's 35-man shortlist, and was expected to be named in the final list of 18 as one of three over-age players.
Goal.com has learned, meanwhile, that Manchester City defender Micah Richards has made the squad despite opting to reject a place on England's five-man standby list for Euro 2012.
Richards returned to the national team set-up in February for a friendly against the Netherlands, but found himself sidelined once more after Roy Hodgson took over as coach.
Craig Bellamy had already confirmed his place in Pearce's plans and fellow Welshman Ryan Giggs is also reportedly set to be involved.
"Everyone knows how much playing for my country has always meant to me," Beckham said in a statement. "So I would have been honoured to have been part of this unique Team GB squad.
|GOLD FOR GB?|
|11/2||Team GB are 11/2 to win Olympic gold this summer|
"Naturally I am very disappointed, but there will be no bigger supporter of the team than me. And, like everyone, I will be hoping they can win the gold."
Beckham, who captained England for nearly six years between 2000 and 2006, had hoped to make a comeback on the international stage. He is the Three Lions' most-capped outfield player with 115 national team appearances to his name.
Now 37, the former Manchester United star last turned out for his country in 2009.