Previous intergenerational communication studies paid only scant attention to acculturation orientation differences in communication between different age groups within a single culture. Many co-cultural groups in the U.S. are encountering emerging acculturation orientation differences between generations. The present study focused on one co-cultural group (Japanese Americans) to gain an understanding of the implications of multiple cultures on the process of intergenerational communication in the U.S. Using Communication Accommodation Theory (CAT), this study particularly investigates the relationships between communication satisfaction, acculturation orientation differences, and communication accommodation among Japanese Americans. A total of 218 Japanese Americans (M[subscript age] = 43.32, SD[subscript age] = 17.69) from across 27 different states participated in the study. The main findings include: (a) generations and age groups did not affect acculturation orientation, (b) comfort using Japanese language varied between the new first generation and the traditional second, third, fourth generations, while comfort using English language was not significantly different across generations or age groups, (c) while integration orientation directly affected communication satisfaction when commutating with older Japanese Americans, assimilation orientation indirectly affected communication dissatisfaction through the use of avoidant communicative behaviour.