In our three pre-registered studies, we aimed to unravel the root and the societal implications of belief in Jewish conspiracy among Indonesian Muslims. Our findings in Study 1 (N=385) confirmed our predictions that symbolic threat and collective narcissism were strongly related to Jewish conspiracy belief and mediated the association between religious zeal and Jewish conspiracy belief. In Study 2 (N=370), we found that Jewish conspiracy belief indirectly predicted vaccination refusal and delay through vaccination conspiracy belief, and observed no evidence to confirm the moderating role of religiosity in reinforcing vaccination conspiracy belief. In Study 3 (N=396), we replicated our findings in Study 2 that belief in Jewish conspiracy theory was strongly related to vaccination conspiracy belief. Also, participants who blamed the Jews for the coronavirus pandemic inclined to refuse coronavirus vaccination if it is available. We argued that religiosity might not directly be related to conspiratorial thinking but instead, it activates a sense of outgroup threats among religious individuals thus they are more likely to endorse Jewish conspiracy theories. Despite the assumption that Jewish conspiracy theory is somehow benign, our findings disputed this premise.