Why do some insurgencies attain their ultimate goal of statehood while others never do? Although explanations for insurgency success based on political will, natural resources, geography or diaspora involvement have advanced our understanding of the conditions under which insurgencies are likely to succeed in pursuing their statehood agenda, they have not adequately addressed the critical role of the major external actors (e.g. USA, UK, European Union, NATO (North Atlantic Treaty Organization)) and how significant these actors are in shaping the fate of many insurgencies around the world. In an effort to develop a model that explains insurgency outcome, this paper argues that external support or lack thereof is likely to shape insurgency outcome. When major external actors support insurgency, the movement is likely to succeed in pursuing its statehood agenda. Otherwise, the movement is likely to reconsider its political agenda if it lacks the necessary external support from major actors. This argument is demonstrated by a comprehensive study and comparison of two cases of insurgency, the Kosovo Liberation Army (KLA) and the Kurdistan Workers’ Party (PKK).