It is argued that threat related to territorial civil wars generates negative interpersonal attitudes that are both more intense and more broadly oriented than previously thought. That is, civil wars fought over issues of autonomy or secession foment social intolerance, a broad orientation that extends well beyond members of former enemy groups to an aversion to interpersonal differences in general. The expectation that the issue the civil war is fought over is consequential is tested with data from the World Values Survey and the UCDP/PRIO Armed Conflict Dataset. The empirical domain consists of over 130,000 individuals across 123 surveys in 69 countries over the 1989–2008 period. Results from multilevel models indicate a positive and statistically significant relationship between domestic territorial conflicts and subsequent social intolerance. Substantively, territorial civil wars have a far greater impact on individuals’ attitudes than do ‘standard’ correlates of social intolerance that are well established in the literature. Further, non-territorial civil war is unrelated to attitudes of social intolerance. Empirical results are robust to several model specifications and are not a mere artifact of the potential reverse relationship, whereby intolerant societies are (erroneously) presumed to be at a higher risk of civil wars in the first place. The findings have implications for the understanding of civil war resolution, civil war reoccurrence, and the contextual correlates of interpersonal intolerance.