The current study examined income disparities in a comprehensive set of preschoolers' outcomes (verbal ability, developmental skills, number knowledge, and hyperactivity) and the factors that could reduce differences in outcomes between children in the lowest and highest household income quartiles. Findings using Cycle 6 data from the Canadian National Longitudinal Survey of Children and Youth demonstrated that children in the lowest income quartile performed the poorest on all outcomes, especially compared with those from the highest income quartile. Household income alone explained 1-6% of the variability in preschoolers' outcomes but accounting for covariates such as child, family, and stimulation in and outside the home increased the proportion of the variability explained to 16-28% and reduced some but not all of the disparities, suggesting the importance of multiple determinants for children's outcomes even in the early years. (author abstract)