Post-truth relates to the combination of tactics of influence and opinion manipulation orchestrated by powerful economic and political interests, principally targeting initiatives or ideas with a transformative potential. Post-truth strategies express themselves in multiple tactics, which happen synchronously at varied levels and through different channels. Scientifically valid information is forced to compete with narratives which are designed to create doubt or skepticism. Disinformation weakens efforts to implement policies intended to support transformative goals. The distortion, discrediting, or ignoring of scientific evidence has become a threat to our societies. This article starts by defining the post-truth phenomenon, first discussing the roots, tactics, and contextual conditions supporting its expansion. Then it explores what stance evaluators can adopt to work in this new era where people are polarized and disinformation is widespread. This article aims to raise awareness of this disruptive phenomenon and brings evaluators together to consider promising practices.