A large conventional wisdom has maintained that economic downturns, which drastically reduce grain prices and the returns to agricultural labor, foment peasant resistance against landowners and state officials. Yet, recent waves of peasant resistance in the developing world have occurred in a prosperous time of extraordinarily high prices. We reconcile these findings by theorizing about the spatial dimensions of peasant unrest. We argue that peasant resistance during a commodities boom takes place in agrarian frontiers — i.e., peripheral areas dominated by small-scale farming and whose soil is less suitable for agroindustrial production. Greater prices encourage landowners from central regions to expand commercial activities into frontiers and encroach the lands of peasant cultivators, thus heightening rural conflict. We further argue that resistance is higher in within-frontier locations where subsistence agriculture is extensively practiced, as it provides a pool of symbolic and material resources to coordinate defensive collective action. We test our claims using municipal-level data from Paraguay between 2000-2013, a period of high prices for the country’s chief export crop: soybeans.