Believing in conspiracy theories is a major problem, especially in the face of a pandemic, as these constitute a significant obstacle to public health policies, like the use of masks and vaccination. Indeed, during the COVID-19 pandemic, several ungrounded explanations regarding the origin of the virus or the effects of vaccinations have been rising, leading to vaccination hesitancy or refusal which poses as a threat to public health. Recent studies have shown that in the core of conspiracy theories lies a moral evaluation component; one that triggers a moral reasoning which reinforces the conspiracy itself. To gain a better understanding of how conspiracy beliefs about COVID-19 affect public health containment behaviors and policy support via morality-relevant variables, we analysed comprehensive data from the International Collaboration on the Social & Moral Psychology (ICSMP) of COVID-19, consisting of 49.965 participants across 67 countries. We particularly explored the mediating role of two levels of morality: individual and group-based morality. Results show that believing in conspiracy theories reduces adoption of containment health-related behaviors and policy support of public health measures, but moral identity and morality-as-cooperation significantly mediate this relationship. This means that beliefs in conspiracy theories do not simply constitute antecedents of cognitive biases or failures, nor maladaptive behaviors based on personality traits, but are morally infused and should be dealt as such. Based on our findings, we further discuss the psychological, moral, and political implications of endorsement of conspiracy theories in the era of the pandemic.