The St. Teresa High School Board of Directors supervises and controls the business affairs of the school. The Board of Directors of St. Teresa High School is responsible for ensuring that the school accomplishes its mission as an accredited Catholic secondary school serving the Decatur, Illinois area. The Board is composed of nine voting directors; one director is a member of the Decatur Deanery of Priests, while eight are lay directors. In addition to the nine voting directors, there are two ex-officio non-voting directors, namely, the Bishop of the Roman Catholic Diocese of Springfield and the school Principal.