This paper contributes to the research on the macroeconomic origins of conflict. Based on a sample of 133 low- and middle-income countries over a 30-year period, it analyses to what extent changes in a country’s commodity terms-of-trade (ToT) can explain an increase in the incidence and intensity of conflicts through their effect on aggregate income. While the evidence from previous studies on the link between macroeconomic conditions and conflict is rather inconclusive, we find a significant relationship. Our baseline model finds that a negative commodity ToT shock leads to an increase in the number of conflict events and fatalities. Moreover, the effect plays out over several years albeit with decreasing strength after the second year; and its magnitude is twice as large for Low-Income Countries and Fragile and Conflict-affected States when compared with the sample average. In addition, our results show that macroeconomic shocks are creating more violence in countries with higher inequality and in cases where fiscal policy faces relatively stronger constraints on financing a response to the initial shock to incomes. Our results are robust to a number of plausible variations in model specification. The paper’s results, in conjunction with previous studies that emphasize the economic cost of conflicts, suggest the presence of a fragility trap—a vicious cycle of worsening economic conditions and deteriorating conflicts. Effective policies and well-tailored external financial support could be expected to help countries address this challenge.