Abstract: This article analyzes the diachronic development of marital naming in Germany and investigates synchronically its legitimization by topoi of reasoning. Based on large registry data from 1976, 1986, 1996, 2006 and 2016, the article shows, how marital naming develops from traditional to more modern forms: instead of choosing the husband’s surname, couples increasingly opt for alternatives, for instance to retain their names or to choose the wife’s name as joint name. This process is accelerated in urban areas compared to rural ones. Moreover, couples with higher education rather choose a non-traditional alternative than couples with lower education. The analysis of topoi of reasoning to legitimize marital naming, based on an online survey from 2019, shows how partners trade off preserving their own individuality against producing a collective family identity. These conflicting needs often bring couples into conflict with each other. This conflict is asymmetrical in terms of gender.