Background: Unhealthy sleep patterns have been linked to a variety of adverse effects in children, and temperament could be an influencing factor in poor sleep quality. Aim: This study examined the association between temperament and sleep quality among preschoolers. Methods: The participants of the study were 35 children aged 3 years to 6 years in Northern Peninsular Malaysia. Observational sleep was recorded across 14 days. Further, a self-administered questionnaire was used to capture the children’s sleep-related issues. The Children’s Behavior Questionnaire-Very-Short-Form was used to measure the temperament of the children. The relationship between sleep patterns and sleep-related issues and temperament was assessed. Results: No significant differences were found between the 3 subscales of temperament sleep duration, and sleep and wake times, for both night sleep and naps. Concerning the association between temperament and children’s sleep issues, a negative weak correlation was found between negative affect and children’s difficulty falling asleep, as well as frequent night-time waking. Effortful control was found to have a weak positive correlation with “sufficient sleep” and “earliness of the sleep,” with a negative correlation for the topic “a child’s bad mood and crying through the day.” Conclusions: The results of this study did not show positive correlations between temperament and quality of sleep among preschool children in Malaysia, though some children’s sleep issue was correlated with temperament. Similar to other studies, these results might be an indication that a child’s difficult temperament could be a factor affecting sleep quality though further large-scale studies will be needed.