This thesis investigates the relationship between generalised trust, heterogeneity and fairness in the EU. High levels of generalised trust have been found to be linked to economic growth and lower transaction costs, while heterogeneous populations have been found to be linked to lower levels of trust. As the world is diversifying on virtually all fronts, a negative relationship between heterogeneity and generalised trust could have dire implications. Other empirical studies have found that heterogenety loses its importance when accounting for societal fairness, speaking to the fact that a fair and democratic society is what determines generalised trust, rather than inter-group differences. But as no such studies have been conducted on contemporary data, it is unknown how the relationship between generalised trust, heterogeneity and fairness holds today. To investigate this relationship, we conducted two-step hierarchical logit regressions on contemporary data, including over 40.000 observations from 23 EU countries. To capture contemporary heterogeneity, we constructed our own fractionalisation indices on this data, as the fractionalisation in- dices most commonly used in previous studies were constructed on data from the 1990s and early 2000s. Our results indicate that both fairness and heterogeneity are significant predictors for generalised trust in the EU. We theorise that this might be because the importance of heterogeneity for generalised trust is context-dependent, only mattering once countries have established a certain level of fairness.