#1 The Wharton School, United States1 / 12 Photo: ShutterstockThe 20-month Wharton (including a recommended 3.5-month summer internship) full-time MBA usually includes a requirement for a major concentration of 4.0 credits, with a choice from 19 majors, plus 5.5 electives in addition to the core curriculum. Offered at the Philadelphia campus, a semester of study at the San Francisco campus is available by application.#1 Stanford