In the more recent works of Judith Butler, the concept of vulnerability plays a key role. Barely any of the many topics, on which the US-American author has been focused since the turn of the millennium, can be understood properly without knowledge of her thoughts about this concept. However, attempting a reconstruction of her concept of vulnerability poses the difficulty that Butlers thoughts about it are scattered across numerous texts, in which different aspects are emphasised and different prioritisations made. In the following article, Butlers work on the theory of vulnerability is concisely presented and interpreted. This is done in the following way: (1) The significance of Butlers deliberations about vulnerability for her notion of materiality of the body is displayed; (2) The relation between vulnerability and approval is explained; (3) It is shown which ethical considerations Butler takes into account based on her conception of approval and vulnerability, and in what way vulnerability and political agency do not exclude each other; and lastly (4) Butlers understanding of vulnerability is confronted with some critical queries.