A central notion among green political theorists is that deliberative engagement enhances environmental values. Despite the centrality of this claim within green political theory, there is a lack of empirical research evaluating its promise outside formal deliberative forums. Here, an empirical large-N study is provided that tests whether everyday political discussion between individuals of different political orientations is positively associated with stronger pro-environmental attitudes in the US. The main finding is that individuals who engaged in this type of cross-cutting discussion reported significantly stronger pro-environmental attitudes compared to individuals who did not engage in this type of discussion. Moreover, the association remained positive for different clusters of individuals regardless of political engagement, party affiliation, or socio-demographics.