Due to the limited evidence on the moderating effect of COVID-19 on functional food purchase intention, this study aims to investigate the factors that significantly predicted the purchase intention of functional foods and the moderating role of COVID-19 on the proposed relationships. In this study, two additional factors (subjective knowledge and health consciousness) are integrated into the Theory of Planned Behaviour (TPB), and the impact of COVID-19 is included as a moderator. Convenience sampling has been employed to collect 294 valid responses from consumers in Malaysia and analysed using the Partial Least Square-Structural Equation Modelling. The findings showed that attitudes, subjective norms and subjective knowledge are significantly related to the intention to purchase functional foods. Results from the moderation analysis further found that the impact of COVID-19 has no significant moderation effect on these relationships. This study provided several tremendous implications to stakeholders such as government agencies, authorities, and businesses as they can refer to the findings to understand the factors influencing consumers to purchase functional foods. For instance, specific policies and strategies have to be implemented by government-related agencies and authorities to enhance further the understanding of the functional foods of the public to encourage them to purchase and consume functional foods to improve their health condition.