This paper evaluates if same-sex marriage (SSM) laws, approved in several European Union countries over the past decades, have contributed to favor gay-friendly opinions among people depending on their social interactions. We propose a dyadic model in which individuals learn about the social norm conveyed by a law through strong and weak ties. We show that the relative importance of these social ties in shaping individuals’ opinions depends on the alignment between the law and the local social norm. Using the 2002–2016 European Social Surveys, we test the theoretical predictions with a pseudo-panel dynamic difference-in-difference setting relying on the progressive adoption of SSM in European countries. We show that strong ties induce a lower increase in gay-friendly opinions following the adoption of SSM when the law is aligned with the local social norm. When the law clashes with this norm, strong ties induce a larger increase.