Objective/Background: Poorer executive function (EF) has been implicated in the etiology of negative parenting (e.g., harsh, reactive, intrusive). EF may be affected by good or poor quality sleep, and thus sleep may be involved in negative parenting. In the current exploratory study, we investigated the additive and interactive effects of maternal EF and sleep indicators in the statistical prediction of negative parenting. Patients/Methods: A sample of 241 mothers of 2.5-year-olds (51% girls) completed questionnaires, wore wrist actigraphs for one week, and completed several EF tasks during a laboratory visit. Results/Conclusions: We found that sleep activity (e.g., nighttime waking and movements) interacted with EF in predicting negative parenting practices, such that poorer EF was linked with more negative parenting only in the context of higher levels of night waking. Sleep duration also interacted with EF, such that EF and parenting were no longer associated when sleep durations were short. The findings have implications for incorporating sleep into our understanding of maternal cognitive self-regulation and harsh parenting during early childhood development.