<p>Changes in family and couple dynamics in Europe since the 1970s have led to a diversification of relationship models, including same-sex cohabitation. However, this phenomenon remains relatively under-researched. This article aims to examine the evolution of the proportion of same-sex cohabiting couples in European countries, linking it to public policies legalizing same-sex unions. It adopts an international comparative approach, taking into account the time dimension. Using data from the Eurostat European Union Statistics on Income and Living Conditions (EU-SILC) survey, our research analyzes data from 31 European countries between 2004 and 2020. The results indicate an increase in the proportion of same-sex cohabiting couples in the majority of European countries. While there are differences in intensity and timing, it appears that countries that legalize both civil partnership and marriage experience the most significant increases in same-sex cohabiting couples. Finally, while legislation may influence the evolution of same-sex cohabitation, it plays only a partial role, and seems to be more in line with changes in the population's demographic behavior.</p>