Given the rise of prescription stimulant misuse, examination of effect expectancies could prove helpful. The Prescription Stimulant Expectancy Questionnaire (PSEQ) was designed to explore positive and negative prescription stimulant-related expectancies. In 2006, 157 participants nationwide completed an Internet survey of prescription stimulant use, attention-deficit/hyperactivity disorder symptoms, and expectancies. Multiple regressions demonstrate that positive, but not negative expectancies, predicted frequency of use. Recreational and medical users were classified by hierarchical cluster analysis. Recreational users reported fewer positive and negative expectancies than medical users. Implications and limitations are discussed. Future research is warranted on prescription stimulant expectancies and the utility of the PSEQ.