Background and research aims. Considering the high prevalence of conspiracy theories and misinformation, there is an urgent need to explain the tendency to adopt a conspiracy mentality and identify behavioural (including voting) outcomes of a high conspiracy mentality. The aims of the present paper are 1) the examination of populist attitudes dimensions, relative deprivation and mistrust of expertise as predictors of conspiracy mentality and 2) proposal of comprehensive models, that combine predictors of conspiracy mentality and its voting consequences. Methodology. Studies utilised OSL regression and structural equation modelling. Results. The overall regression was statistically significant. It was found that dimensions of populist attitudes (anti-elitism, sovereignty), relative deprivation and mistrust of expertise were significant predictors of conspiracy mentality. In line with the second research aim, the fitness of models was confirmed and results suggest mistrust of expertise is also a significant predictor of far-right voting. Discussion. The contribution of the paper lies in connecting conspiracy mentality with not only attitudes but also with important behaviour outcome - voting behaviour. We propose future research should experimentally examine whether the reduction of some of the identified predictors could possibly lower levels of conspiracy mentality and whether this reduction translates into voting behaviour.