Post-truth politics has been diagnosed as harmful to both knowledge and democracy. I argue that it can also fundamentally undermine epistemic autonomy in a way that is similar to the manipulative technique known as gaslighting. Using examples from contemporary politics, I identify three categories of post-truth rhetoric: the introduction of counternarratives, the discrediting of critics, and the denial of more or less plain facts. These strategies tend to isolate people epistemically, leaving them disoriented and unable to distinguish between reliable and (...) unreliable sources. Like gaslighting, post-truth politics aims to undermine epistemic autonomy by eroding someone's self-trust, in order to consolidate power. Shifting the focus to the effects on the victim allows for new insights into the specific harms of post-truth politics. Applying the concept of gaslighting to this domain may also help people recognize a pernicious dynamic that was invisible to them before, giving them an important tool to resist it. (shrink)