This thesis examines the status of the military in modern normative republican theory. In classical republicanism there is a strong relation between the republic and the military, which was envisaged to perform three critical internal functions in a republic: preventing executive tyranny, promoting civic virtue and providing the best civic engagement for the citizens that produces common good. However, a study of modern republicanism reveals a diminishing emphasis on the role of military. Some prominent advocates of contemporary republican theory have little or no role for it in their conceptualization, while there are still some advocates who believe either military itself or its civic alternatives can and should contribute to effective functioning of the republican system. I argue that military may not be central as it was before, but if a modern state needs to keep military, it can still contribute to motivational and institutional challenges of republicanism. These contributions will only be possible if military can be established as a democratically-controlled institution that will not abuse its power to de-politicize the political realm and thwart citizens’ capacity for self-rule. In addition, I also argue that removing the central concept of citizen-army from republican theory will create inconsistency unless same functions are performed by other means.