["Family Relations, Volume 75, Issue 2, Page 977-996, April 2026. ", "\nABSTRACT\n\nObjective\nWe examined relationships among parental self‐efficacy, parent–child interaction quality, and child vocabulary in families of low socioeconomic status (SES).\n\n\nBackground\nSES is correlated with child vocabulary, but this relationship is mediated by parenting characteristics, as explained by the family stress and family investment models. Here, we explored parental self‐efficacy because it is associated with both SES and parenting behaviors that support child development.\n\n\nMethod\nParental self‐efficacy, sociodemographic, and household data were measured at baseline in a sample of 89 low‐SES mother–child dyads. Parent–child interaction quality was assessed from video recordings (child age M = 12.01 months) and vocabulary was assessed via parent report (child age M = 25.09 months). Comparisons of means, correlations, and mediation analyses were conducted.\n\n\nResults\nNo mean differences in parent–child interaction quality or child vocabulary were found based on sociodemographic or household traits. Parental self‐efficacy and parent–child interaction quality were correlated, as were parent–child interaction quality and child vocabulary. Parent–child interaction quality fully mediated the relationship between parental self‐efficacy and child vocabulary.\n\n\nConclusion\nParental self‐efficacy relates to child language development indirectly through its positive effect on parenting behavior.\n\n\nImplications\nTargeting parental self‐efficacy for intervention alongside parent–child interaction skills may improve parenting quality and children's subsequent development.\n\n"]