When and why do rebels hire private military actors? I argue that rebels are more likely to hire private military actors under the conditions of power asymmetry, rebel competition, the presence of lootable resources and when rebel groups have effective leadership and organizational structures. I test three hypotheses empirically using the PSED dataset which identifies that rebel hired private military actors account for nearly 10% of all PMSC/mercenary employers in Africa, Latin America, and Asia from 1990-2012. I find strong empirical support that power imbalances between rebel groups and government, and the presence of lootable resources increases the likelihood of employment. Counter to my expectations, I find that rebel competition reduces hiring. A qualitative analysis shows that rebel groups with parent organizations are more likely to hire private military actors.