Publicly funded center-based preschool programs were designed to enhance low-income children's early cognitive and social-emotional skills in preparation for kindergarten. In the U.S., the federal Head Start program and state-funded public school-based pre-kindergarten (pre-k) programs are the two primary center-based settings in which low-income children experience publicly funded preschool. Although evidence suggests that these programs generally promote cognitive and social-emotional skills for low-income children overall, whether the benefits of program participation vary for low-income children with difficult temperaments is unexplored. Difficult temperament status is a source of vulnerability that connotes increased risk for poor early school outcomes-risks that may be ameliorated by public preschool programs known to promote kindergarten readiness among other vulnerable populations. Using a nationally representative sample of low-income children (N ≈ 3,000) drawn from the Early Childhood Longitudinal Study-Birth Cohort (ECLS-B), this study tests whether associations between public preschool participation and children's cognitive and social-emotional skills in kindergarten are moderated by difficult temperament status. We focus on Head Start and public school-based pre-k, comparing both with parental care and with each other. Results provide weak evidence that public preschool's benefits on children's cognitive and social-emotional skills in kindergarten are moderated by child temperament. School-based pre-k is significantly associated with better reading skills relative to parental care only for children with difficult temperaments. Additionally, for children with difficult temperaments, Head Start is significantly associated with better approaches to learning relative to parental care, and with reduced externalizing behavior problems relative to school-based pre-k. (PsycINFO Database Record (c) 2019 APA, all rights reserved).