 This entry begins by describing the nature of rights: their classification, their composition, and their function. It then reviews the history of the language of rights, and various relationships between rights and reasons. The major contemporary philosophical approaches to the justification of rights are compared, and the entry concludes by surveying criticisms of rights and “rights talk.” The focus throughout is on general theoretical issues (what rights are) and not on arguments over specific rights (what rights there are). Those looking for fuller introductions to rights may consider Jones (1994), Harel (2005), Campbell (2006), Ivison (2007) and Edmundson (2012).