The Weinstein Co. announced the rating change on Thursday. The Motion Picture Association of America initially gave the film an R rating for language, meaning kids under 17 were restricted from seeing it without an accompanying adult.
The MPAA refused to change the rating when The Weinstein Co. appealed. The film was released March 30 in limited release without a rating.
"Bully," directed by Lee Hirsch, is an examination of school bullying that follows five kids over the course of a school year. The Weinstein Co. says three uses of an expletive were removed to earn the PG-13 rating.
Supporters of the film had rallied along with The Weinstein Co. to get the original version a lower rating.
The ruling ends a month-long dispute between The Weinstein Co. and the MPAA over the rating that prompted 17-year-old high school student Katy Butler of Ann Arbor, Mich., to start an online petition calling for a lower rating so more young people can see it.
Johnny Depp, Meryl Streep and New Orleans Saints quarterback Drew Brees were among the celebrity supporters of the film.
The edited version of "Bully" is set to be released April 13.
The Associated Press contributed to this report.