Sleep disorders are prevalent among college students and are associated with poor academic performance. Few studies have included a clinical interview to comprehensively assess sleep disorder diagnostic criteria or assessed academic functioning (e.g., class attendance). College students (n = 277) were recruited to complete sleep questionnaires, a sleep diary for two weeks and, if indicated, a semi-structured clinical interview. Based on questionnaire data, students were categorized as being at risk versus not at risk for a sleep disorder. Based on the semi-structured clinical interview, students were categorized as meeting versus not meeting diagnostic criteria for a sleep disorder. Academic performance and functioning were assessed in all students to determine the association between the presence of sleep disorders and academic performance and functioning. In models adjusted for age, sex, race, and credit hours completed, students at risk for a sleep disorder (38.6% of the sample) reported missing more classes due to oversleeping (p = 0.001) and illness (p = 0.014), and fell asleep in class more often (p = 0.030) than their peers not at risk. Students with a sleep disorder (24.8% of the sample) reported missing more classes due to illness (p = 0.024) than those without a sleep disorder. There were no differences in grade point average between students at risk versus not at risk or with versus without a sleep disorder. Sleep disorder symptoms and diagnoses were significantly associated with worse academic functioning but not performance. Assessment and treatment of sleep disorders early in college students’ career may be important for optimal academic functioning.