The Graduate School of Applied and Professional Psychology (GSAPP) was established in 1974 to train direct-service psychologists who have a special commitment to community involvement. The school offers the doctor of psychology (Psy.D.) degree in professional psychology with specializations in the areas of clinical psychology and school psychology, and awards the master of psychology (Psy.M.) degree en passant to the doctorate (the Psy.M. is not offered as a terminal degree). GSAPP also offers a master of applied psychology (M.A.P.) and a dual-degree program for a B.A./M.A.P. in coordination with the School of Arts and Sciences. Certificate programs in applied behavior analysis and alcohol and drug studies are also available for individuals at the master's and postbaccalaureate level of training. In addition, the school offers a continuing education program, through its Office of Professional Development and Continuing Education, that benefits practicing psychologists and other mental health professionals.

The current interim dean is Ryan Kettler. Past deans include Donald R. Peterson (1974-1989), Perry London (1989-1992), Sandra L. Harris (1992-2001), Stanley B. Messer (2001-2016), Francine Conway (2016-2020), Denise Hien (interim 2020-2021).