Mitigating climate change requires collective action of various sectors and on multiple scales, including individual behavioural changes among citizens. Although numerous studies have examined factors that influence individuals’ mitigation behaviours, much less attention has been given to interpersonal influence. Children have been suggested to influence parents’ climate change concerns; however, how the interactions between couples—typically the primary decision-makers in married-couple households—influence each other’s climate change concerns has seldom been discussed. In this study, we surveyed married heterosexual couples to investigate the interdependency of husbands’ and wives’ motivations for behavioural change to mitigate climate change. We found that wives’ psychological constructs, including climate change risk perception, self-efficacy, and gender role attitudes, demonstrated stronger effects on their husbands’ motivation than did husbands’ own constructs on their own motivation, whereas husbands’ psychological constructs did not influence their wives’ motivation. Our results suggest the importance of wives’ role in motivating household climate change mitigation behaviours.