This paper examines the role of social norms and political polarization in shaping vaccination attitudes and behaviors in the context of the Covid-19 pandemic. Using a large-scale representative survey experiment in Turkey, we first show that political affiliation is a strong predictor of attitudes towards vaccination. We then use standard economic games to measure the extent of polarization caused by subjects’ attitudes towards vaccination. We find that pro- and anti-vaxxers discriminate each other substantially. Furthermore, when pro- and anti-vaxxers perceive a political difference between them, this polarization is exacerbated. Finally, using randomized informational treatments, we show that the promotion of a broadly shared social identity might mitigate this outgroup discrimination.