Homeless children show significant developmental delays across major domains of adaptation, yet research on protective processes that may contribute to resilient adaptation in this highly disadvantaged group of children is extremely rare. This study examined the role of effortful control for adaption in 58 homeless children, ages 5-6, during their transition to school. Effortful control skills were assessed using children's performance on four standard laboratory tasks. Adaptive functioning was assessed by teacher report of academic competence, peer competence, and internalizing and externalizing symptoms. Variable-focused and person-focused results indicate that effortful control may be an important marker of school readiness and resilience. Controlling for child IQ, parenting quality, and socio-demographic risks, effortful control emerged as the most significant predictor of all four salient developmental domains of adaptation as well as of resilient status of homeless children. Implications of these findings are discussed for future research and design of interventions. (Contains 5 tables.)