This short textbook provides an introduction to queer theory, exploring its key genealogies and terms as well as its application across various academic disciplines and to contemporary life more generally. The authors engage with a wide range of developments in queer theory thinking including discussions of identity politics, transgender theory, intersectionality, post-colonial theory, Indigenous studies, disability studies, affect theory, and more. In offering an updated reflection on the present tensions that queer theory must negotiate, as well as its unfolding future(s), is an ideal resource for anyone starting out on their queer theory jourbaney; for students who want to get a grasp of the basic concepts, for teachers looking for a textbook for their queer theory course, or for scholars who want a quick go-to resource for key queer theory ideas and terms.