Associations between infant temperament, maternal stress, and infants’ sleep across the first year of life

•Numerous sleep outcomes were examined longitudinally across the first year of life.•Temperament was related to sleep problems, sleep latency, and night wakefulness.•Maternal stress was related to day sleep duration.•Sex differences were found for sleep latency and night sleep duration.•Infant and maternal characteristics affect sleep differentially. Effects of temperament and maternal stress on infant sleep behaviors were explored longitudinally. Negative temperament was associated with sleep problems, and with longer sleep latency and night wakefulness, whereas maternal stress was associated with day sleep duration, suggesting infant and maternal characteristics affect sleep differentially.