Children's purchase influence (CPI) is an important factor in understanding family consumption behavior. The present study investigated the effects of cultural adaptation, including the role of acculturation and ethnicidentification, on children's role in family purchase decisions. By conceiving of CPI as a family context-dependent phenomenon, we hypothesized that parent-child cultural dissonance/consonance within the family influences CPI through a cross-level process. The hypotheses were tested on data collected from 99 Hong Kong Chinese immigrant family triads, i.e., father, mother, and a teenage child. The results showed that: (1) acculturation positively and ethnicidentification negatively influenced CPI for most products, (2) the interaction between acculturation and ethnicidentification had a positive influence on CPI, and (3) generational dissonance/consonance had significant moderating effects on CPI through a cross-level route.