Purpose– The family and specifically, the partners of expatriates are unfortunately the major cause of expatriate maladjustment. Drawing from and extending the concept of relational demography, the purpose of this paper is to examine the influence of the nationality of expatriates’ partners, conceptualized as host, home or third country nationality, on expatriates’ cross-cultural adjustment.Design/methodology/approach– Survey data from 299 expatriate academics in China, Japan and South Korea were analysed. The authors used confirmatory factor analyses to validate the scales and ANCOVA to test the hypotheses. To further understand the interactions effects the authors conducted simple slopes analysis.Findings– Results show that differences in expatriate academics’ cross-cultural adjustment are notper sebased on the different nationality of their partners, but are mainly due to an interaction effect of partner nationality and length of stay in host country. Expatriates with host country national partners perceived the highest increase in cross-cultural adjustment over time, followed by those with third country national partners, whereas those with home country partners did not experience any increase in cross-cultural adjustment.Research limitations/implications– The study was based on a cross-sectional survey of expatriate academics in Asia. Thus, longitudinal, multisource data from various contexts would increase validity and generalizability of findings. Despite these limitations, the study provided new and intriguing findings. The theory and empirical evidence underscore the importance of expatriate partner nationality and thereby, relational demography between expatriate partners and expatriates.Practical implications– The research aims to emphasize the important role that expatriate partners can play concerning the success of expatriate cross-cultural adjustment. Greater attention should be paid to the adjustment processes of expatriates and their partners to facilitate expatriate cross-cultural adjustment.Originality/value– The authors are among the first to study the influence of nationality, conceptualized as host, home country or third country nationality, of expatriates’ partners on expatriates’ cross-cultural adjustment by applying the concept of relational demography. Moreover, the authors look at the role that time in the host country has on the partner’s influence on expatriate adjustment.