Los Angeles Superior Court Judge Michael Levanas ruled Friday that Winter's 34-year-old sister Shanelle Gray will remain the 15-year-old's temporary guardian pending a trial in October on whether the arrangement will be permanent.
Gray was awarded temporary custody after her sister claimed mental and physical abuse by their mother, Chrisoula Workman, who has denied the accusations.
Winter's father, Glenn Workman, will remain in charge of the actress' finances. He was put in control of the teen's business interests in December as part of a temporary agreement by everyone involved, which included extending Gray's guardianship.
However, Chrisoula Workman later changed her mind, saying she opposed Gray's guardianship role. Chrisoula Workman's lawyer said he plans to call about a dozen witnesses during the trial to prove the entire guardianship issue should have never occurred in the first place.
Winter's court-appointed lawyer said he will call witnesses from the Department of Children and Family Services.
City News Service contributed to this report.