As a general rule, a child is emancipated, or freed from parental control, care and custody, upon reaching the age of 18 or upon graduation from high school if a child turns 18 in his or her senior year. In Ohio, emancipation also can occur before that time if the child gets married or joins the military service. While many people think that someone under 18 can go to court and get emancipated, Ohio law does not provide for such a court order. There is no form that one can fill out to become emancipated. Rather, circumstances determine whether or not a person is emancipated in the eyes of the law.
To read more, go to this article from the Ohio State Bar Association: http://www.ohiobar.org/Pages/LawYouCanUseDetail.aspx?itemID=255