<p>Food waste exemplifies the inefficiencies, inequities, and unsustainability embedded in contemporary food systems, with consumption identified as the stage where the most food is discarded. In university settings, food waste has emerged as a pressing concern, as individuals often display a higher tendency for wasteful behaviour during young adulthood. It is crucial to explore the underlying factors behind young population’s food waste behavior to develop effective policies, particularly for emerging economies, where return on income for food needs to be efficient. This study investigates the factors influencing university students’ tendencies to leave plate waste in the cafeteria of one of Turkey’s most populous universities. We used an extended version of Theory of Planned Behaviour framework, by adding perceived portion size, taste and palatability, and self-reported environmental behaviour on students’ food waste generation. We employed a mixed-methods approach, including a face-to-face questionnaire conducted with 479 students and subsequent in-depth interviews with 11 participants to further explore these drivers. The findings reveal that situational variables, perceived portion size, and taste and palatability, significantly influence students’ food waste behaviours in the university cafeteria, often outweighing their volitional control. The less concerned young consumers are about the environment, the more plate waste they tend to produce within the cafeteria setting. These insights point to the need for targeted, context-sensitive strategies to reduce food waste in institutional settings.</p>