AbstractReligious and conspiracy beliefs are based on the assumption that a potent force exists which is capable of affecting people’s destinies. According to compensatory control theory, the belief in such a potent external agent may serve to alleviate feelings of uncertainty and help restore a sense of control. This is of particular relevance and importance to attitudes and behaviour of religious individuals towards vaccinations during the Covid-19 pandemic, where a belief in such a potent external force controlling events and destinies may have lowered the sense of threat posed by Covid-19 and in turn reduced vaccination uptake. To test this, we conducted a cross-sectional study of highly religious adults in Poland (N = 213) and found that the number of COVID-19 vaccine doses taken was negatively predicted by conspiracy beliefs, perceived closeness to God, and frequency of church attendance, and positively predicted by the perceived COVID-19 threat. Furthermore, mediation analysis revealed that both conspiracy beliefs and perceived closeness to God were related to a decreased perception of the COVID-19 threat, which in turn led to a decreased number of vaccine doses received. Our study offers important insights for public health professionals and identifies further research pathways on conspiracy and religious beliefs in relation to health-related behaviours.