Building on prior national case studies of the economic consequences of civil conflict, this paper articulates and analyzes a theory of external debt accumulation by states during and immediately after civil conflict. The demands of military and public goods provision on state leaders are a matter of political survival during civil conflict, which drives an economically unwise but politically indispensable increase in the external debt burden. The composition of this debt burden is affected by the presence and intensity of conflict, which then affects bilateral lending, multilateral finance, and aid in distinct ways. Default is also considered as a means of conflict financing by states, given the importance of conflict financing. The findings broadly support the importance of disaggregating the dynamics of debt and default during civil conflict.