This article uses weather shocks to interstate population movements in India between 1982 and 2000 to recover the causal effects of migration on rioting. We find evidence of a substantively and statistically significant effect of migration on riots. We also investigate the mechanisms by which migration causes riots. India was the generating case for the seminal theory of internal migration and violence—Myron Weiner’s sons of the soil theory, which holds that migration is destabilizing when there is high unemployment among natives.8 But we do not find that the effect of migration is greater in places with higher unemployment among natives.