Personal characteristics such as populism, conspiracy theories, and political orientation have an impact on citizens' decision to engage in sustainable behaviors (Van der Linden, 2015; Prasad, 2019; Evensen, 2019; Lamb et al., 2020; Giuliani & Presaghi, 2023). However, due to the eclecticism of populism (Sensales, 2021), this construct does not seem to influence pro-environmental behaviors in a univocal way (Dalby, 2020; Ruitenberg, 2020; Lamb et al., 2020; Huber et al., 2021; Chazel & Dain, 2023). Therefore, the study aims to determine whether populism and conspiracist beliefs affect the adoption of pro-environmental behaviors and whether political orientation moderates these effects. Preliminary analysis on a sample of 288 Italian participants showed a significant positive indirect effect of populism on motivation towards sustainable behaviors (b = .322, se = .199, IC 95% .026; .787) through conspiracist beliefs among right-wing voters, but not among left-wing respondents. Results will be discussed according to the literature.