Emotion regulation (ER) is a source of risk and resilience for psychological development and everyday functioning. Despite extensive research on various early contextual predictors of child ER capacity, few studies have integrated them into the same study. Therefore, our longitudinal study investigated the joint and independent contributions of several prominent contextual predictors of child ER capacity. We followed typically developing children and their caregivers (N = 118, 47% girls) at three time points (children ages 10, 12, and 18 months). At 10 months, mothers reported household chaos, social support, and parenting stress, and maternal sensitivity was observed and coded with the Ainsworth’s Maternal Sensitivity Scales. At 12 months, child–mother attachment security was assessed using the Strange Situation Procedure. Finally, at 18 months, child ER was obtained with a Laboratory Temperament Assessment Battery frustration task. Correlational analyses revealed that household chaos and maternal sensitivity were significantly positively associated with child ER. Multiple regression analyses showed independent effects of household chaos and maternal sensitivity on child ER. Our partly counterintuitive results underscore the significance of cumulative risk and protective factors for ER development and suggest that household chaos and maternal sensitivity may contribute uniquely to better ER in typical toddlerhood.