The present study examines the role of a Vietnamese heritage language school in cross-cultural adaptation, as operationalised by the confluence of two independent variables, language competence and integrated cultural identity. To characterise the students' language competencies and degree of integrated cultural identities, interview questionnaires of virtually a complete census of students in the school were analysed via descriptive statistics. Correlation and regression analyses were conducted to determine relations between each independent variable and demographic factors (such as age at arrival in the USA and family milieu) and to determine relations between each independent variable and school factors (such as pattern of attendance and class participation). The findings suggest the heritage school experience was related to components of Vietnamese language competency but had little impact on integrated cultural identity. Age at arrival in the USA and family milieu played a more significant role in the cross-cultural adaptation process.