On the background of a growing global emphasis on sustainable consumption and the need to understand how environmental and health consciousness influence green food preferences, this research investigates the psychological factors influencing Vietnamese consumers' transition to green food choices. Building on the Theory of Planned Behavior (TPB), we extend the model by incorporating environmental and health consciousness two additional constructs to understand their impacts on green food purchase intention and behavior. Data was collected from 569 consumers in Hanoi in face-to-face interviews, and Partial Least Squares Structural Equation Modeling (PLS-SEM) was used for analysis. Key findings reveal that green food purchase intention is a strong predictor of actual purchase behavior. Perceived behavioral control and social influence significantly affect purchase intention, while positive attitudes towards green food also play a crucial role. Besides, environmental concern has a significant impact on attitudes and green food purchase intention, because it plays an essential role in promoting sustainable consumption. In addition, health consciousness directly affects the purchase intention of green food but does not change overall attitude, indicating that health-related motives are distinct drivers of green food purchases in the Vietnam market. Our study is a unique contribution to the literature by the integration of environmental and health consciousness into the TPB framework and its application in a developing country context. The findings offer practical implications for policymakers and businesses aiming to encourage sustainable consumption patterns in Vietnam.