As global rates of overweight and obesity continue to rise, there is an acknowledgment that prejudice and discrimination against those who are perceived to be ‘Fat’ (Anti-fat prejudice; Obesity Stigma) is increasing, and is a significant problem for society. This stigma has been found to have significant negative social, psychological, economic, and health outcomes for those who are discriminated against based on their weight status. In the presentation I will first examine the reasons why people stigmatise those who are perceived to be fat. I will then present the research on the negative impact of such stigmatisation on the individual, including a discussion of the physiological (hormonal responses), psychological (e.g., self-stigmatization, anxiety, depression, sleep problems), and behavioural consequences (eating behaviours, social isolation). Finally, I will discuss potential avenues for reducing this stigma in order to reduce its significant negative social and health consequences.