This study used data from the Head Start Family and Child Experiences Survey (FACES) 2009 4-year-old cohort to examine associations among family characteristics, home and classroom environments, and the emergent literacy skills of Head Start children. Results from hierarchical linear models suggest that both family and classroom contexts play a unique and interactive role in supporting Head Start children's development of different sets of emergent literacy skills. Parental warmth was positively related to children's oral language skills (i.e., receptive and expressive vocabulary knowledge), and teachers' educational level and the quality of instructional support in the classroom were significantly associated with children's code-related skills (i.e., letter-name and letter-sound knowledge). Further, high-quality instructional support in the classroom buffered the negative influence of low maternal education on children's oral language skills. Interventions focusing on enhancing the quality of parent-child interactions, in addition to professional development for teachers designed to improve the quality of instructional support, may contribute to promoting the development of emergent literacy skills of young children from low-income families.