On the determinants of political polarization

•We study the determinants of political polarization using a BMA approach.•Trust and income inequality are robust determinants of political polarization.•Higher trust decreases political polarization.•Higher income inequality increases political polarization.

In this article, we aim to identify the main determinants of political polarization using Bayesian Model Averaging to overcome the problem of model uncertainty. We find that the level of trust within a country and the degree of income inequality are the most robust determinants of political polarization.