This entry examines the phenomenon of post-truth in its relation to the notion of the possible. It starts by outlining the roots and main characteristics of the post-truth context, including its relation to politics, social media, and post-modernist assumptions about the relativity of truth. While the spread of falsehoods and lies is not uncommon across the history of society, what makes the current trend particularly alarming is the fact that we are dealing with more than distortions of what is true; we are witnessing a growing disregard, in the case of some individuals and groups, of reality itself. To overcome the pitfalls of relativist accounts, what we need is a recognition of the fact that the possible is not the opposite of the real but its ever-present companion. And, also, that cultivating possibilities, including in the form of “possible truths,” should be guided by ethical question about what these truths “do” for self, others, and society.