In this paper, we study the effect of displacement of population into cities on urban conflict in developing countries. To do so, we construct a novel measure of exposure to floods, using data on more than 3300 flood events worldwide, as an exogenous source of population displacement. We combine this with city level observations of thousands of urban social disorder events over the period 1985–2015. Exposure to floods is found to be associated with higher intensity of urban social disorder. Our evidence suggests that the effects of floods on urban disorder occur in part through the displacement of population into large cities. Exploring the information on urban disorder events in more detail, we find that the association between city growth and urban disorder is strongest for events related to public service provision, prices, and wages.