The question of whether laws affect attitudes has inspired scholars across many disciplines, but empirical knowledge is sparse. Using longitudinal survey data from Norway and Sweden, collected before and after the implementation of a Norwegian law criminalizing the purchase of sexual services, we assess the short-run effects on attitudes using a difference-in-differences approach. In the general population, the law did not affect moral attitudes toward prostitution. However, in the Norwegian capital, where prostitution was more visible before the reform, the law made people more negative toward buying sex. This supports the claim that proximity and visibility are important factors for the internalization of legal norms.