Mobile banking (M-bank), a newly introduced technology, can improve women’s access to financial services. This study empirically estimates the effect of a husband’s and wife’s socioeconomic characteristics, relative differences in age and education, and household characteristics on M-bank use in northern Bangladesh, exploring the presence and possible effect of the gender gap between husband and wife. A couple’s relative differences in age or education can function as a proxy to capture the wife’s M-bank use, thereby, her financial responsibilities in the household. The empirical evidence is based on a two-equation probit estimation that predicts the possible determinants of M-bank use by husbands and wives. M-bank use of husbands and wives differed remarkably, with wife to husband ratio of 4:15. Households were categorized into three subgroups: wife user, husband user, and nonuser. Results show that a husband’s level of education, having his own business, and having a migrant family member within the household have a statistically significant positive effect on the likelihood of him using M-bank. On the other hand, a wife with an education level higher than that of her husband’s has a significant positive effect on the likelihood of her using M-bank. A substantial gender gap in M-bank use, favoring husbands, was observed in most couples where the husband has more schooling than the wife and vice versa. The impact of M-bank use must be critically studied, focusing on the couple’s relative status due to the gender gap in educational attainment and positive relative characteristics of couples in patriarchal, Islamic, rural settings in Bangladesh.