Beckham, who has been a figurehead for London throughout the bidding process and the build up to the Games, had looked certain to be one of three over-age players selected by Pearce.
But the 37-year-old has been overlooked, in favour of Micah Richards, Craig Bellamy and Ryan Giggs.
Olympic football rules state that only three players over the age of 23 can be selected in the squad.
Beckham, who plays for American side LA Galaxy, is still expected to attend the Games, and may have a part to play in the opening ceremony.
This is the first time that Britain has submitted a football squad to the Games since 1972.
The British Olympic Association (BOA) has maintained that it will not interfere with Pearce's squad selection, despite the absence of football's most well known player.