In this article, I present an argument for a proposed focus of ‘critical costume’. Critical Costume, as a research platform, was founded in 2013 to promote new debate and scholarship on the status of costume in contemporary art and culture. We have now hosted two biennial conferences and exhibitions (Edge Hill University 2013, Aalto University 2015). These events have exposed an international appetite for a renewed look at how costume is studied, practised and theorized. Significantly, Critical Costume is focused on an inclusive remit that is interdisciplinary and supports a range of ‘voices’: from theatre and anthropology scholars to working artists. In that regard, I offer an initial argument for how we might collectively navigate this interdisciplinary field of practice with reference to other self-identified critical approaches to art and design. By focusing on an interdisciplinary perspective on costume, my intention is to invite new readings and connections between popular practices, such as Halloween and cosplay, with the refined crafts of theatrical and film professionals. I argue that costume is a vital element of performance practice – as well as an extra-daily component of our social lives – that affords distinct methods for critiquing how appearance is sustained, disciplined and regulated. I conclude by offering a position on the provocation of critical costume and a word of caution on the argument for disciplinarity.