Conspiracy theories spread through social and other media often bringing easy explanations of events that cannot be easily explained. Beliefs in conspiracy theories may lead to simplified and radical viewpoints that can negatively influence one's behavior and actions. The paper analyzes the association between beliefs in popular conspiracy theories spread through social media and work performance using the results of an authors’ test of conspiracy theories applied to a sample of 178 students of the Faculty of Military Leadership, University of Defence in Brno, Czech Republic. The students were selected as representatives of high-profile professions that should be trained to deal with potential disinformation and conspiracy theories. The assumption was that the students would be generally immune to the impact of conspiracy theories. The analysis did not confirm a hypothesis that individuals with top work performance are less prone to beliefs in conspiracy theories than individuals with solid/poor work performa