With academic procrastination prevalent at every level of education (O'Brien, 2002; Onwuegbuzie, 2008), school psychologists and other educators would benefit from a more detailed look at procrastination and what factors and characteristics mediate it. This exploratory study investigated the relative contributions of Executive Functioning, Perfectionism, and Frustration Intolerance to Academic Procrastination and investigated whether academic procrastinators can be classified into specific clusters. To achieve this, 150 undergraduate and graduate students completed an online survey assessing Executive Functioning, Perfectionism, and Frustration Intolerance. Although no distinct clusters of procrastinators formed, results indicated that Perfectionism and irrational beliefs associated with frustration intolerance were the strongest mediators for academic procrastination. These results could aid mental health professionals, therapists, and school psychologists in recognizing these traits and patterns early to develop more specific treatments, interventions, and possible prevention of academic procrastination. Keywords: academic procrastination, irrational beliefs, executive functioning, perfectionism.. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]