Insomnia is characterized by nighttime disturbances and daytime impairments, including fatigue, concentration difficulties, reduced sustained attention, and mood disturbances. Evening chronotype may represent a risk factor for both bedtime procrastination and insomnia; however, these relationships have not been thoroughly examined. A total of 671 adults participated in the study. The sample consisted of 191 men (Mage = 28.56, SD = 12.08), 473 women (Mage = 31.89, SD = 12.61), and 7 individuals identifying as other (Mage = 30.71, SD = 16.08). Participants completed an online survey that included the Chronotype Questionnaire, the Bedtime Procrastination Scale, and the Athens Insomnia Scale. Evening chronotype was positively correlated with both bedtime procrastination and insomnia. Mediation analysis revealed that bedtime procrastination mediated the association between evening chronotype and insomnia symptoms. These findings underscore the role of circadian preferences in shaping sleep-related behaviors such as bedtime procrastination, which may contribute to the development of insomnia. Addressing circadian and behavioral factors may enhance the effectiveness of insomnia prevention and intervention strategies.