Interethnic relationships are increasingly common in many societies, yet interethnic couples have a higher divorce rate compared to intraethnic couples. Given these facts and the dearth of research, this study aimed to identify factors that contribute to couples’ commitment in interethnic relationships. This study investigated the personal commitment of Chinese interethnic couples in the United Kingdom and the United States. Specifically, whether love, dyadic adjustment and “couple cultural identity” (i.e. acculturation to the partner and couple’s similarity on individualism/collectivism) would predict personal commitment and whether each variable would account for unique variance in personal commitment of the participants. Thirty-seven Chinese/non-Chinese heterosexual couples participated in the study and significant relationships between love and personal commitment, dyadic adjustment and personal commitment were found. Also, couple cultural identity was important for women’s personal commitment. Multiple regression and structural equation modelling showed that partners in interethnic relationships defined personal commitment in different ways with men emphasizing love and dyadic adjustment, and women emphasizing love and acculturation to their partner. The discovery of the importance of couple cultural identity in contributing to personal commitment, besides love and dyadic adjustment, helps researchers to gain a greater understanding of such relationships and to extend the research on interethnic relationships.