Public opinion on COVID‐19 provides new empirical evidence for the debate on the ideological contours of conspiracy theories. I report findings from a web survey in Greece where participants were recruited via paid advertising on Facebook and the study sample was adjusted for age, gender, education, domicile, and region of residence using a nationally representative reference sample. I find that beliefs about conspiracy theories are more correlated than the values associated with established political ideologies, and that conspiracy beliefs and scepticism about the pandemic are best explained by belief in unrelated political and medical conspiracy theories. No other demographic or attitudinal variable has such a strong influence, and the results are robust to different statistical specifications. In comparison, the effect of ideology measured by left‐right self‐placement is rather negligible and further moderated by trust in government. The results have implications for the strategies aimed at fighting disinformation during public health emergencies.