Chambers was elected to the Legislative Assembly of Ontario in the provincial election of 2003, as a Liberal in the riding of Scarborough East, defeating incumbent Progressive Conservative Steve Gilchrist by over 7000 votes. The Liberals won the provincial election, and Chambers was appointed Minister of Training, Colleges and Universities on October 23, 2003. In early 2004, she reaffirmed her government's election pledge not to raise tuition rates.