The question of nothingness occupies the thinking of a number of philosophers in the first half of the twentieth-century, with three of the most important responses being those of Henri Bergson, Martin Heidegger, and Jean-Paul Sartre. Surprisingly, however, there has been little discussion of their specific comments on nothingness either individually or comparatively. This paper starts to remedy this by suggesting that, while Bergson dismisses nothingness as a pseudo-problem based in a flawed metaphysical understanding, Heidegger, in What is Metaphysics?, claims (...) that metaphysics entails a covering of being meaning that Bergson’s analysis actually depends on and so brings thinking to a questioning of being. In turn, Heidegger’s insight acts as the transitional point for Sartre who criticizes Bergson’s description of nothingness to show that, following Heidegger, nothingness is a real ontological problem. From this insight, Sartre distinguishes between negativity, nothingness, and nihilation to show that the issue of nothingness is intimately connected to the freedom of human consciousness, which, by distinguishing between ontological and practical freedom, reveals that nothingness has ethical and political significance. By way of conclusion, a number of problems in Sartre’s account are identified. (shrink)