Self-regulation develops rapidly during the toddler years and underlies many important developmental outcomes, including social-emotional competence and academic achievement. It is important to understand factors that contribute to early self-regulation skills among children at risk for adjustment difficulties in these domains, such as children growing up in poverty. The current study examined mother-reported child temperament (negative affect, effortful control) and observed maternal parenting (during a mother–child free play) as contributing factors to toddlers’ observed self-regulation during delay of gratification tasks at 27 months (snack delay) and 33 months (gift delay). Participants were 198 toddlers (Mage = 27 months; 53% boys; 48% non-Hispanic white) and their mothers from low-income families. Mothers’ negative parenting characterized by negative affect, hostility, and negative control was associated with poorer self-regulation contemporaneously. Toddlers’ lower negative affect and higher effortful control predicted better self-regulation at 33 months, but positive parenting characterized by positive affect and sensitivity moderated these associations at both time points. Specifically, we found a buffering effect of high positive parenting among toddlers with a temperamental risk and a deleterious effect of low positive parenting despite toddlers’ temperamental strength. Results highlight the importance of positive parenting for fostering the development of self-regulation among toddlers growing up with poverty-related and child-level risks.