Beauvoir’s existentialist ethics relates to and informs eminently contemporary accounts of feminist ethics in the Western continental feminist canon. To date only a few scholars have emphasized this connection. In this work, I show the centrality of Beauvoirian philosophy to contemporary philosophical discussions by elucidating the influence of Beauvoir’s existentialist ethics on Judith Butler’s feminist philosophy. While I acknowledge other possible influences, especially by French philosophers, on Butler’s work, I find it important to emphasize Beauvoir’s contributions as they have not (...) received the attention they deserve. My paper shows how Beauvoir’s account of agency as an ambiguous becoming reverberates in Butler’s theory of gender performativity developed in her early writings. I consider Butler’s theory of gender performativity to have existentialist roots based on the existentialist perception of the subject as a becoming that never coincides with itself. I also discuss how Butler takes on some basic ethical questions which Beauvoir already accentuates in her writings. I focus on three main points of intersection between the two philosophers, which are vulnerability and interconnectedness, violence and inevitability of ethical failure, and finally the ambiguity and opaqueness that come with situated ethics. (shrink)