Objective: Increasing numbers of students with attention-deficit/hyperactivity disorder (ADHD) are attending college; however, little empirical information is available concerning the functional impairment experienced by these students. Although preliminary studies suggest that college students with ADHD are more likely to experience a variety of psychosocial and academic difficulties compared to their peers without the disorder, findings regarding neuropsychological functioning have been inconsistent with some studies reporting that college students with ADHD perform more poorly on various cognitive and neuropsychological tasks while others report no differences compared to their peers without ADHD. Method: The purposes of the present study, the Trajectories Related to ADHD in College project, a longitudinal study following the 4-year outcomes of college students with and without ADHD, were to (a) examine the performance of 436 first-year college students with and without ADHD (51.6% female) on measures of executive function (EF) and intelligence and (b) investigate the association of self-reported use of stimulant medication and neuropsychological performance in students with ADHD. Participant data from their first year of involvement in the study were analyzed. Results: Participants with ADHD performed more poorly on task-based and self-report EF measures relative to the comparison group. In contrast, no significant group differences were found with respect to intellectual performance. Within the ADHD group, use of prescription stimulant medication was associated with improved performance on some, but not all, neuropsychological tasks. Additional analyses also revealed significant group differences in EF based on clinical diagnostic status. Conclusion: College students with ADHD demonstrated poorer EF than their peers without ADHD and psychostimulant medication was associated with improved EF performance. No group differences were found with respect to intellectual functioning, Lastly, having one or more comorbid psychiatric diagnoses in addition to ADHD was associated with poorer EF outcomes.