Obesity bias is the tendency to negatively judge an overweight or obese individual based on assumed and/or false character traits, such as being physically unattractive, incompetent, lazy and lacking self-discipline. Obesity biases, such as teasing or weight criticism during physical activity (PA), can be psychologically or emotionally damaging for overweight children and adolescents. Ultimately, the effects students experience over time may create a psychological barrier and students can become resistant to schools' health and PA interventions that promote lifestyle changes. Fortunately, the psychological effects of obesity bias are mediated by social buffers and coping mechanisms. Several PA-related researchers have proposed strategic intervention components, but no studies have been completed in PA settings. The purpose of this review was to discuss the nature and different types of obesity bias in PA settings. Major theoretical frameworks of the aetiology and change mechanisms of obesity biases from the psychological literature were reviewed and direct applications for strategic component interventions were made for PA settings. Because of the pervasiveness and entrenchment of obesity bias, it is obvious that multiple theoretical frameworks need to be considered and even combined to create safe and caring school PA environments for students.