Oyedele has been with Man United since 2012, progressing through the various age groups at the club, but he is still waiting to make his first-team debut for the Red Devils.
The 19-year-old, who had a youth loan at Altrincham last season, has played in Premier League 2, the EFL Trophy and the UEFA Youth League during the 2023-24 campaign.
Oyedele has one goal and one assist in eight Premier League 2 appearances this term, while he turned out against Stockport County and Bolton Wanderers in the EFL Trophy earlier this season.
Oyedele, who is also capable of playing as a defender, qualifies to represent Poland through his mother, and he has featured on three occasions for Poland Under-21s.
"I'm very excited to be here and I'm looking forward to getting started," the teenager told Forest Green's official website upon completion of the loan deal.
"I will bring energy to the group, professionalism and quality as well. I will let loose and give it my all. There will be no stone unturned.
"I believe we can climb up the table, that's why I've come here, so I'll be doing everything I can to help with that."
Meanwhile, Forest Green head coach Troy Deeney added: "Maxi is a wonderful talent and we're extremely lucky to have him here.
"The fans will enjoy watching him and we need to make sure we get him in a place where he can showcase his talents."
Oyedele, who will wear the number 22 shirt for Rovers, has made the move to a club that are currently bottom of the League Two table, boasting only 18 points from 26 league games this season.
The youngster is the sixth player to leave Man United on loan this month, with Alvaro Fernandez (Benfica), Hannibal Mejbri (Sevilla), Joe Hugill (Burton Albion), Jadon Sancho (Borussia Dortmund) and Donny van de Beek (Eintracht Frankfurt) also departing Old Trafford in the winter window.