Isotretinoin is commonly used to treat acne, and its effects on sleep have been documented. However, its impact on chronotype features remains unclear. This study aimed to investigate the effect of isotretinoin on sleep duration and chronotype features, considering body mass index (BMI), anxiety, and depression levels as covariates. Among the 106 participants, 55 were systemic-medication-free for acne treatment, and 51 were in their sixth month of isotretinoin therapy. Acne severity was assessed using the Global Acne Grading System. Participants completed the Pittsburgh Sleep Quality Index, the Reduced Morningness–Eveningness Questionnaire, and the Hospital Anxiety and Depression Scale. Sleep duration was significantly shorter in the isotretinoin-treated group compared to the systemic medication free group. A tendency toward an evening chronotype predicted the likelihood of being in the isotretinoin-treated group. In the follow-up of patients undergoing isotretinoin treatment, a psychodermatological perspective should include consideration of sleep duration and chronotype features.