This paper explores the relationship between two models of behaviour: the theory of planned behaviour; and the self determination theory, to develop insights into ethical consumption, specifically organic food shopping. It was found age is a key variable that influences a consumers¿ intention to purchase. This has implications for how marketing strategies are developed in order to influence consumption of goods based on ethical considerations. Specifically, it appears that when targeting young people, it is important to establish ethical attitudes that are rewarded consistently. For older people, it may be necessary to develop strategies for overcoming `ethical fatigue¿ by appealing to their need for autonomy and subjective norm compliance.