Culture plays an important role in socio-emotional development. Within the context of close relationships, culture can influence the way we think about and relate to others. However, the transactional associations between close relationships and culture may differentially influence socio-emotional development at different developmental stages. Moreover, existing literature on culture and socio-emotional development lack ecologically-valid measures and rarely take into account the element of time. The goal of this dissertation is to examine how cultural factors may affect socio-emotional development by (i) using ecologically valid approaches and (ii) taking into account the element of time. Study I examined the relations between cultural orientations, intrusive parenting, and child adjustment in Chinese American immigrant families. Participants were Chinese American children and their parents from first- and second-generation immigrant families. Observed intrusive parenting behaviors were coded from videotaped parent–child conflict discussions. Findings indicated that there was a unique positive association between child Chinese orientation and child-reported intrusive parenting, a unique negative association between parents’ American orientation and child-reported intrusive parenting, and a unique positive association between child American orientation and observed intrusive parenting. Intrusive parenting was negatively associated with child adjustment, but associations varied depending on measurement. Findings suggest that different measures of intrusive parenting are differentially associated with children’s adjustment in Chinese American immigrant families. Study II expanded upon the findings of Study I to examine culture and socio-emotional development within a different developmental period and a different cultural context. Specifically, Study II examined endorsement of cultural values in Latinx emerging adults using an intensive longitudinal design. Participants reported on their cultural values, social environment, and socio-emotional wellbeing twice a day for 14 consecutive days. Using multilevel modeling, findings suggest substantial variation of cultural values at the within-person level. Follow-up analyses indicated that facets of the social environment, including occurrence of social interaction, who the interaction person was, quality of social interaction, closeness of relationship, and belongingness were consistently associated with interdependent, but not independent values. Furthermore, interdependent values were associated with better socio-emotional wellbeing in Latinx college students, but this pattern was not found for independent values. These findings highlight the need to study changes in culture as a function of the social environment, and the need to measure culture using ecologically valid measures that allow for more sensitive and dynamic assessments. Taken together, this dissertation presented testable, hence replicable means to examining the complex relationships between the macrosystem (culture), the microsystem (close relationships), and the chronosystem (time).