How does the organizational legacy of a rebel group affect its ability to survive within a conflict? I theorize that adopting the institutional structure from a parent organization can strengthen the rebel group’s ability to resist the government. By drawing upon literature that identifies how such a pre-established structure is complementary to, or serves as a substitute for an informal system of social control, I posit that rebel groups emerging from a pre-existing organization are less likely to get militarily defeated by the government than rebel groups without a parent organization. I test this hypothesis empirically by using the FORGE dataset that identifies not only whether rebel groups emerge from pre-existing organizations, but also from which type of parent organization. I find that only rebel groups with a pre-existing parent organization that has an institutional base pre-designed to resist repression from the government in order to avoid their militarily defeat have positive implications on rebel groups’ durability. In contrast, rebel groups that emerged from the military and non-military faction of the government are found to be more prone to a militarily defeat by its parent.