This paper is an attempt to delineate the concept of the deep state and assess its value in understanding aspects of authoritarian and illiberal politics. Driven politically by a logic of tutelage and exercising a high degree of autonomy, the deep state justifies itself through the need to defend the nation against purported existential threats. The paper began by expanding on the term, discussing which elements are central to the concept of the deep state and which are not. Secondly, it related the deep state to a number of other concepts in comparative politics. The paper then briefly considers these elements to address the contexts in which a deep state may emerge before looking at cases of deep states in Turkey, Pakistan, and Iran.