It is argued that science denialism brings about an aberrant form of enquiry that deviates in significant ways from the epistemic norms governing scientific enquiry. Science denialism doesn’t involve just a rejection of a scientific theory; it also challenges the practice of continuously and impartially testing research methods, theories, and evidential sources with the aim of improving the accuracy of our theories. This chapter provides an in-depth analysis of the epistemic mechanisms at work. It develops a fine-grained framework to model a variety of normative deviances that may take place in enquiry. Through analysing two case studies, it is argued that fake news plays two pivotal roles in shaping epistemic norms operating within science denialism. First, it discredits a variety of (institutional) sources of evidence; second, it also plays a part in building the alternative explanation of the target phenomena.