Leonna Barrett is the main antagonist of the 1989 film Lean on Me.
She was portrayed by the late Lynne Thigpen.
She is a mother of one of the expelled teenagers from Eastside by Joe Louis Clark. She aligns herself with the mayor, Don Bottman in an effort to oust Clark. The fire chief eventually catches Clark with chains on the doors and Barrett makes a tape recording of him ordering them removed during a surprise inspection. Clark was sent to prison, but the mayor is preparing to remove him and the entire student body converges on the Central Office of the Paterson Board of Education.
Barrett tries to convince the students that Clark has made too many wrong decisions and is not the right man for principal of Eastside, and asks that they return to their homes before any trouble starts. The students claim that Clark cares for them and has done so much good that they will not accept anyone else as their principal and that she never did care for them, and shout down Barrett with chants and cheers, but she refuses to to step down. Clark is freed from custody, and to good news: enough students passed the basic skills exam, which means the current administration will retain control over the school. With that, Clark shuns both Barrett and the mayor: "You can tell the state to go to hell!" And with this, she angerily blames the mayor for her defeat.