Odelusi's initial month-long stay at the Milton Keynes club expired after their thrilling 3-2 win at Stevenage on Saturday.
"Sanmi is a testament to any young player because of his exceptional work ethic and his desire to want to play football," Dons boss Karl Robinson told the club's official website.
"He's made an impact both on and off the pitch since he's arrived and we're delighted to be able to keep him until the end of the season. Importantly, he wanted to stay too.
"I'd like to thank Dougie Freedman and Bolton for allowing us to get this deal done."
Odelusi, 20, has made six appearances for the Dons so far and has started the last four games.