Student development theory (SDT) is a diverse corpus of academic and popular psychology with real-world application to the maturation of college and university students. It originated during the campus upheavals of the 1960s as part of a collective effort to reconcile restive students to mass higher education and modern technological society. Then, in the 1970s, SDT was implemented and refined by an ambitious generation of student affairs professionals eager for institutional influence and academic legitimacy. By providing an animating moral and intellectual purpose to the bureaucratic sundering of student affairs divisions from academic affairs divisions, SDT abetted a lasting institutional and cultural change in the organization of the modern university circa 1970. As a discourse of therapeutic empowerment, SDT has had an enduring influence on the daily practice of student affairs administration in the five decades since.