Social fragmentation is often associated with reduced co-operative behaviour, which undermines public goods provision (such as environmental protection). The few studies linking social fragmentation and environmental performance have been confined to using ethnic fractionalisation as the only measure of social heterogeneity. In this paper, we contribute to the literature in a twofold manner. First, we bring into the analysis alternative measures of social fragmentation (i. e. religious fractionalisation, ethnic/religious polarisation), that have received considerable attention in development economics in recent years. Second, this is the first study to our knowledge that makes use of a large panel dataset of several environmental indicators to explore links between ethnic/religious diversity and the environment. We find that all indices of social fragmentation are negatively linked to measures of environmental quality, although for some of them the size of the effect is larger in the case of polarisation.