Narrative language abilities are foundational to literacy development and are a culturally grounded measure of early literacy for Latino children. This study evaluates the impacts on narrative language abilities and the costs of a 4-week, strengths-based program that leverages two valued sociocultural practices with built-in benefits, personal narratives, and family food routines (e.g., grocery shopping), for improving Latino kindergarteners' learning outcomes in the United States. Two-hundred and 34 children (M age = 67 months; 51% girls; 13 schools) and their parents participated in a cluster randomized trial. Children produced personal narratives at three time points: pretest, end-of-treatment, and 5-month follow-up. Four narrative features were measured: narrative coherence, elaborations, word types, and literate language features. Large positive impacts were observed on all four narrative features at the end-of-treatment posttest (d = 1.21-1.76). There was suggestive evidence of moderate impacts on one narrative feature (i.e., narrative coherence) at the 5-month follow-up (d = 0.59). The costs required to implement the family program were relatively low. Findings highlight the potential value of implementing this strengths-based program in schools serving Latino kindergarteners using a rigorous evaluation of its effectiveness. [This article is published in "Developmental Psychology" (EJ1338851).]