The 37-year-old former England captain has spent the past six seasons with the Galaxy, leading Los Angeles to an MLS Cup title last season when they defeated the Houston Dynamo 1-0.
Beckham and the Galaxy go for their second consecutive crown when they face the Dynamo in a repeat of last year's final on December 1 at the Home Depot Center.
Beckham said the game would be his last for the team as he hopes to move on and eventually become a part-owner of an MLS team in the future.
“I've had an incredibly special time playing for the LA Galaxy. However, I wanted to experience one last challenge before the end of my playing career,” Beckham said.
“I don't see this as the end of my relationship with the league as my ambition is to be part of the ownership structure in the future.”
Beckham did not go into specifics about what he meant by “one last challenge” or what he plans to do next.
There have been reports out of Australia last week that their professional league is trying to woo him to make a move down under. There has also been strong interest from European clubs.
Beckham has scheduled a news conference for Tuesday in Los Angeles where the Galaxy said he would discuss his future in more detail.
“This is his final competitive game with the Galaxy,” said Galaxy spokesman Justin Pearson.
Pressed for more details about Beckham's future plans, Pearson said Beckham will speak on Tuesday but he didn't know what Beckham was going to say.
“He said what he said,” Pearson replied. “It will be discussed tomorrow. Whether or not answers are there is unknown.”