This study focuses on the association of noise levels and noise variability with children's wellbeing in home-based childcare. The sample contained 103 toddlers with their caregivers. Wellbeing was observed by independent researchers during three 8-minute episodes of regular childcare activity. Noise levels in decibels were measured during these observation episodes. Average noise level and noise variability (i.e., the average standard deviation of noise level across observation episodes) were related to child wellbeing, over and above child and childcare characteristics. Both relations were nonlinear: only when observed scores rose above a critical threshold, noise and noise variability were negatively related to wellbeing. We found no interaction effects for child gender, age, and temperament. Results indicate that noise variability as well as average noise level matters for child wellbeing in home-based childcare. (author abstract)