Virtual reality (VR) technology can promote sustainable consumption and pro-environmental behaviour. However, few studies have examined the psychological mechanisms that promote sustainable purchase intention from the perspective of VR education. Based on the self-determined motivation theory and VR attributes, this study proposes and empirically examines the underlying mechanism of VR customer knowledge education on sustainable purchase intention. The results show that VR customer knowledge education has a positive effect on customers’ sustainable product knowledge levels, and subsequently, on sustainable purchase intention through the two mediators of knowledge richness and usefulness. Additionally, customers’ intrinsic (versus extrinsic) learning motivation leads to a higher sustainable knowledge enhancement effect. Nonetheless, this effect is moderated by customers’ prior sustainable knowledge; customers with low (versus high) prior sustainable knowledge are more susceptible to the effects of VR customer knowledge education.