Background: Poor sleep quality is associated with a broad range of psychopathology and is a common problem among college students. This study aimed to investigate the mediating role of metacognitive beliefs related to sleep, emotion regulation and a negative cognitive style related to anxiety (looming cognitive style) in the relation between neuroticism and subjective sleep quality. Participants: Participants were 343 undergraduates from three universities in Tehran (56.3% females, Mean age = 22.01±2.74 years). Method: Data were gathered with a questionnaire packet that included the Pittsburgh Sleep Quality Index (PSQI), Metacognitions Questionnaire-Insomnia (MCQ-I), Emotion Regulation Questionnaire (ERQ), Looming Maladaptive Style Questionnaire (LMSQ) and Neuroticism subscale of NEO-PI-R. Results: Structural equation modeling analyses supported a proposed model (R 2 =37%) which proposed that neuroticism both directly and indirectly linked to subjective sleep quality through 2