Background <p>Children’s temperamental traits, such as rhythmicity, reactivity, and persistence, as well as bedtime routines, play a crucial role in influencing their sleep behaviors.</p> Objective <p>The present study examined the contributions of the children’s temperament (rhythmicity, reactivity, and persistence) and bedtime routines to children’s sleep problems, with a further interest in examining the moderating role of bedtime routines between child temperament and sleep problems.</p> Method <p>The sample consisted of 313 mothers of children aged between 16 and 84 months (M = 52.42, SD = 12.36). The mothers provided reports on their children’s sleep problems, bedtime routines, and temperament.</p> Results <p>Hierarchical regression analyses were run to test hypotheses. Results indicated that children’s temperamental rhythmicity and reactivity were closely linked to sleep problems, with bedtime routines, especially a consistent bedtime environment, helping to reduce these issues. Consistent bedtime practices moderated the effect of low rhythmicity, as children with lower rhythmicity experienced fewer sleep problems when routines were stable.</p> Conclusions <p>Regular bedtime routines may serve as a protective factor, mitigating the effects of challenging temperamental traits on sleep.</p>