The defensive midfielder, younger brother of former Reds star Wes, has endured a difficult campaign so far with injuries limiting his appearances for Warren Joyce's side. But Brown now hopes to kick on with the npower League One club and show what he can do.
"I've had previous loan spells at Bradford City and Doncaster Rovers and they are all part of the learning curve," Brown told Oldham's official website.
"This has been a frustrating season so far as I've only played six matches because of hamstring and hernia injuries.
"It will be a privilege to play for Oldham. I want to help the team and learn from playing first-team football against players who are bigger and quicker."
Brown's move to Boundary Park means there are now nine United players out on loan, from Kiko Macheda at QPR in the Barclays Premier League to John Cofie with Royal Antwerp in the Belgian Second Division. Find out how they're faring in Loan Watch, every Monday on ManUtd.com.