This article explores the patient experience of medically unexplained symptoms (MUS) from an existentialist standpoint. Drawing on the work of Jean-Paul Sartre and Simone de Beauvoir, I explore their concepts of existential situation, existential project, authenticity, and praxis. I then analyze the situation of MUS patients in the current cultural and institutional context, elucidating that a lack of explanation for their symptoms puts MUS patients in an existential bind. I illustrate the effects of the experience of MUS on patients’ existential (...) projects. Last, I develop an ethical response in the existentialist tradition from the perspective of patients, providers, and society at large. I argue that there is a collective responsibility to foster conditions more conducive to authentic patient well-being and to improve the experience of patients with medically unexplained symptoms. (shrink)