Do democracies and autocracies intervene militarily in different types of civil conflict? In contrast to the existing literature that makes no distinction between military interventions undertaken by democracies and those by autocracies, I argue that democracies and autocracies are likely to intervene in different types of civil conflict. Specifically, I find that an increase in the rebel capabilities and the existence of an ethnic tie between the rebel group and the third-party state will increase the probability of a military intervention favoring the rebel group only when a third-party state is democratic. The evidence also shows that an autocracy is more likely to intervene when there are lootable natural resources such as secondary diamonds in a civil conflict, but there is no effect of lootable resources on a democracy’s intervention decision. The analytical framework in this paper can apply to other types of military behaviors and would provide a more accurate picture of the effect of regime type on foreign policy choices.