In this work I aim to offer a theory of moral subjectivity of the state that helps to explain, in an analytically sound way, what is required for theorising about states as moral agents within a system of very different types of state-units, and, furthermore, enables one to explore what kind of consequences the practices of moral subjectivity might have for that very same system. The argument that I present has two levels. The first level consists of two theoretical claims about exploring the moral subjectivity of the state in International Relations. The first claim is that in order to argue meaningfully about the moral subjectivity of the state one has to take seriously the state's being-in-theworld qua state. By relying on Immanuel Kant's political philosophy and practical metaphysics, I will offer a theory that is applicable when one wishes to conceptualise the state as an autonomous entity in its own right, and, subsequently, allows one to argue that all states, despite their different prudential and contingent differences and characteristics, are moral agents. The second theoretical claim is that the moral personhood of the state is not in and of itself merely metaphysical – that it is, in fact, something purely intrinsic to the agent. Here I depart from Kant's original idea of essentialist moral personality of the state, and, in contrast to Kant, argue that the moral subjectivity of the state is always reciprocal. Moral subjectivity, therefore, cannot be studied without the concept of moral standing: the agent's positioning among other similar entities. Moral subjectivity proper is then constituted by recognition of other similar subjects who consider themselves as moral subjects. Moral subjectivity is always conditional and placed under scrutiny by politics of recognition. The second level of the argument maintains that when one then studies practices of moral subjectivity of the state – that is, states vis-à-vis each other in international society – it is the recognition of subjectivity that plays a central role in identifying states as moral agents in world affairs. While every state in theory qualifies as a moral person, their moral standing as fully-fledged moral subjects is constantly challenged due to their empirical differences in practice. One such difference explored in this study is the liberal/non-liberal character of the state. In order to make sense of the claims of different and sometimes even contradictory moral statuses of different types of empirical states in world politics, I argue that one has to explore the practices of moral subjectivity as well.