The purpose of this study was to examine how young children's homes and preschool programs influence kindergarten achievement by being "ready environments." Ready environments provide opportunities for cognitive and social growth through culturally and developmentally appropriate activities, interactions, and materials. This study used kindergarten assessments, and parent and teacher questionnaires from the Early Childhood Longitudinal Study-Kindergarten Cohort database. Data from more than 10,000 kindergarten children were analyzed to determine if learning activities in the home and preschool attendance had an impact on young children's cognitive skills in kindergarten. The results showed that learning activities in the home had an influence on children's approaches to learning. Preschool attendance had a significant positive effect on children's reading and math achievement in kindergarten. Recommendations for how to support parents and increase preschool attendance for all children are provided. (Contains 2 tables.)