Research Findings: In this study, 75 Spanish-speaking preschoolers (M age = 41.43 months, SD = 10.78 months; 30 girls) attending a Migrant Head Start program were randomly assigned to receive the Storytelling for the Home Enrichment of Language and Literacy Skills (SHELLS) in addition to their Head Start services (n = 32) or to continue to receive their typical Head Start services (n = 43). Mothers' language-supporting behavior and home language and literacy environment as well as children's total number of words and total number of different words used during a shared narrative were assessed before and after the intervention. Mothers in the SHELLS group, compared with mothers in the comparison group, were significantly more likely to increase their use of language elicitation strategies and the quality of their home language and literacy environment. Children in the SHELLS group, compared with children in the comparison group, were significantly more likely to increase the number of total words and different words in the shared narratives from pretest to posttest. Practice or Policy: These results suggest that this culturally sensitive, strengths-based family intervention can be successful in supporting children's language and literacy with families who face multiple challenges related to poverty, language, and migration. (Contains 3 tables and 5 figures.)