The 29-year-old "She's the Man" actress first enrolled at the school in early 2014 but took a break before she was went under a psychiatric hold, reported Us magazine.
"We are all so proud of her, and can't wait to see her amazing designs on the runway someday," her parents' lawyer Tamar Arminak said.
Bynes has been keeping a low profile since she went through a treatment for her erratic behaviour last year.