Objective: Given the mixed literature in the area, the aim of the current study was to determine whether sex differences exist in inattention, hyperactivity, and impairment in college adults with ADHD. Method: Individuals from three universities were recruited for the study. Participants with (n = 164) and without ADHD (n = 710) completed on-line measures of symptoms and impairment. Results: College women with ADHD were shown to have higher rates of inattention, hyperactivity, and impairment than college women without ADHD and college men with ADHD. Analyses revealed that women in college who have ADHD experience higher levels of impairment in the following domains: home life, social life, education, money management, and daily life activities. Conclusion: Overall, clear differences emerged between men and women with ADHD. Implications and future directions are discussed. (Contains 3 figures and 2 tables.)