According to uncertainty management theory (UMT), organizational justice helps individuals to cope with uncertainty. Employees will thus respond stronger to organizational justice when uncertainty is high. We contribute to UMT by highlighting poor socioeconomic conditions, specifically, weak rule of law, low human development, and high income inequality, as salient sources of uncertainty. We argue that when these conditions are unfavorable, the effects of organizational justice on employee reactions will be stronger than when they are more favorable. We test our arguments using a meta-analysis of 279 studies involving 315 samples from 31 countries. Our findings suggest that poor socioeconomic conditions raise the strength of the relationship between organizational justice on the one hand and task performance and organizational citizenship behavior on the other but not the relationship between organizational justice and counterproductive work behaviors. Our study responds to recent calls to place greater emphasis on contextual factors and to close the macro–micro gap in the literature on organizational justice.