Understanding factors that contribute to weight suppression across eating disorders as well as unique factors that may promote weight suppression for specific disorders is an important field of study. Weight suppression is the difference between highest past body weight and current weight, and has been associated with weight gain, continuation of binge eating and purging, and longer duration of illness in bulimia nervosa and anorexia nervosa. There is existing research to suggest that eating behaviours and body dissatisfaction may promote weight suppression differently depending on the eating disorder. The aim of the current study was to understand how temperament dimensions (novelty seeking, harm avoidance, reward dependence, and persistence), eating behaviours and body dissatisfaction predict weight suppression in a sample of 301 women with a primary diagnosis of anorexia nervosa, bulimia nervosa, or binge eating disorder. Anorexia nervosa was associated with higher levels of weight suppression followed by bulimia nervosa, and binge eating disorder was associated with the lowest weight suppression. Higher harm avoidance (characterised by inhibiting behaviours to avoid negative outcomes, experiencing worry, being fearful of uncertainty, and shyness with new people) and more frequent food restriction were found to positively predict weight suppression in the combined sample. Anorexia nervosa, bulimia nervosa, and binge eating disorder diagnoses were examined as possible moderators of the associations among eating behaviours and weight suppression, and body dissatisfaction and weight suppression. No moderation effects were found. These findings suggest that weight suppression is a transdiagnostic risk factor and contribute to understanding how temperament and eating behaviours promote weight suppression and can be applied to promoting healthy weight. Targeting harm avoidance in eating disorder treatment could promote healthy eating and recovery by alleviating the negative impact of weight suppression.