Abstract Individual differences in morningness–eveningness (M/E) or chronotype are related to many aspects of personality. Here, we assessed the relationship between the behavioural inhibition (BIS) and activation system (BAS) in relation to M/E and sleep timing in 291 University students. We used two measures of M/E, a clock-time based measurement and a preference scale. BAS Drive was related to morningness and BAS Fun Seeking was related to eveningness concerning both M/E measurements. Drive was higher in morning oriented students and Fun Seeking was higher in evening oriented students. Total BAS score was unrelated to the M/E measures because the subscales were correlated with M/E in different directions (one positive, one negative). BIS Fear was related to morningness based on midpoint of sleep (MSF) suggesting that fear was higher in morning oriented students. Total BIS scores were also related to morningness. Concerning the Big Five, we could show that evening orientation was related to extraversion based on midpoint of sleep, and morning orientation to conscientiousness in both M/E measures.