Research Findings: This study examines patterns of sibling relationship qualities or interactional types and their association with family characteristics, parenting, and the characteristics of 1 of those children. Participants were 65 children (34 boys; Time 1 mean age = 51 months), their mothers, fathers, and Head Start teachers. Approximately 95% of the mothers and 92% of the fathers were of Mexican descent. Measures of parenting and children's problem behavior were completed during the spring (Time 1) of the 1st year of the study. Sibling relationships were assessed twice the next year (Times 2 and 3). Family emotional expressivity and cultural values were obtained at Time 2. Three clusters emerged from analyses: warm, average, and affect-intense. Results revealed that the sibling relationship type characterized by high warmth and low agonism was associated with supportive and democratic parenting and positive family expressivity as reported by mothers. Mothers' "simpatía" and fathers' "familism" were associated with sibling warmth. Reports of externalizing behaviors achieved the highest mean values for the affect-intense group. Practice or Policy: Results demonstrate the feasibility of a multidimensional approach to the study of young children's sibling relations as well as add to researchers' understanding of sibling relations in families of Mexican descent.