In 2011, the Taiwanese Government began a campaign to encourage new immigrants to teach their native languages (heritage languages) to their children. However, these heritage languages are seldom used in cross-national families and the effectiveness of formal heritage language courses in Taiwan has yet to be explored. The present study examines the influence of school and family support on children's attitudes towards heritage language learning. A structured questionnaire was developed and sent to 234 primary school pupils whose mothers are Vietnamese and fathers are Taiwanese. Results revealed that: (1) the immigrant mothers who speak Vietnamese at home with their children increased their children's motivation to learn Vietnamese as a heritage language; (2) the pupils reported that they received limited school support in their Vietnamese courses; and (3) the children who live with their immigrant parents are more motivated to learn Vietnamese than those who do not. The implications of these findings are discussed.