This study examined the developmental changes of familism values across adolescence among Latinx adolescents from an emerging immigrant community, and how changes in parental warmth were associated with changes in familism values. The sample included 547 Latinx adolescents. Multilevel model results indicated that familism values showed a linear decline from 6th to 10th grade. Between-person analyses showed that parental warmth was related to the higher initial levels of familism values but unrelated to changes in familism values. At the within-person level, on the occasions when adolescents report higher parental warmth, they also report higher familism values. This work highlights the importance of parental warmth for socializing developmental changes in Latinx adolescents’ familism values in an emerging immigrant community context.