To have moral status (moral standing or moral consideration) is to be an entity toward which moral agents have or can have moral obligations. Beings of moral status have certain moral rights; morally wrong can be done to them. The concept has emerged from applied ethics discussions about medical ethics, animal ethics, and environmental ethics in the 1970s. Subsequently it continued to be important in discussions of applied ethics, particularly bioethics. Many moral status theories such as the moral agency theory, the genetic humanity theory, the sentience theory, the organic life theory, the biosocial theory, etc. have been put forward as to which entities have moral status on what grounds. In this paper, we will examine the concept and theories of moral status. For this, we will divide the study into three parts. In the first part, we will examine the definition, emergence and importance of the concept of moral status. In the next section, we will examine the theories of moral status by categorizing them into graded and non-graded, degreed and non-degreed, and uni-criterial and multi-criterial. In the last part, we will try to evaluate these types by comparing them. As a result of this assessment, we will argue that degreed theories of moral status seem more plausible than non-degreed theories of moral status.