To better understand the nature of impairment resulting from attention-deficit/hyperactivity disorder (ADHD) for students in a post-secondary education (PSE) setting, the authors analyzed the symptoms and associated impairment of 135 students with a diagnosis of ADHD who were recruited via Student Disability Services in Canadian post-secondary institutions. The authors (a) developed a novel semistructured telephone interview based on the 6-item Adult ADHD Self-Report Scale Screener–Telephone Interview With Probes (ASRS-TIPS) to elicit students’ descriptions of their behavior for each symptom they endorsed, (b) administered standardized tests of executive functioning (EF) and academic fluency, and (c) obtained self-reports of grade point averages (GPAs), EF, cognitive failures, psychopathology, distress, and resilience. Qualitative analysis of the ASRS-TIPS revealed significant impairment relating to symptoms of ADHD in the PSE setting. Students reported clinically significant symptoms of ADHD, psychological distress, and impairment in EF (67%, severe range) and cognitive failure (62%, atypical range) in everyday life. By contrast, their GPAs and standardized scores of EF and academic fluency were in the average range. Standardized scores and GPAs did not capture the impairment that participants experienced in their PSE settings. The ASRS-TIPS may provide a useful tool to help document how these students’ symptoms impair functioning in the PSE setting.