This study aims to identify the determinants influencing consumer purchase intention towards red palm oil as a functional food with the application of an extended Theory of Planned Behavior (TPB) among Malaysian consumers. A total of 370 data were collected via mall intercepts in Malaysia using convenience sampling. Partial least squares (PLS) analysis was used to evaluate the measurement and structural model of the study. The results demonstrated that attitudes, subjective norms, and perceived behavioral control have a positive and significant relationship with the purchase intention of red palm oil as a functional food. Additional variables like food involvement, environmental concern, perceived value, and perceived risk significantly affect consumers' purchase intention of red palm oil as a functional food. Surprisingly, there is no effect between food neophobia and healthy lifestyle purchase intention. The results showed that TPB constructs confirmed its explanatory influence on purchase intention and an extended TPB model with additional variables demonstrated a better explanatory interpretation of the purchase intention of red palm oil as a functional food. This paper concludes with implications of the study and the limitations and suggestions for future research.