Childhood overweight and obesity is a significant and increasing health problem both nationally and globally. Yet few interventions for preventing obesity have been successful, particularly in the long-term, suggesting that important factors are being overlooked. The aims of this thesis were to investigate (a) the prevalence of childhood overweight, obesity, and binge eating; and (b) the relationships between body weight, binge eating behaviour, and a set of physical, psychological, and psychosocial variables including parent body size, body dissatisfaction, size-related teasing experiences, internalisation of sociocultural messages, depression, dieting attitudes and behaviour, and emotional eating. Participants were 569 grade five and six primary school children (272 boys and 297 girls) from Catholic and Government schools across metropolitan Melbourne, Australia. Almost 25% of participants were classified as overweight or obese. Thirteen percent of participants reported engaging in overeating (with or without loss of control), 14% reported loss of control (with or without overeating), and 6% reported engaging in binge eating (overeating and loss of control). Structural equation modelling analyses found that body weight and binge eating were indirectly related. Body weight was directly and positively associated with parent body size, size-related teasing experiences, body dissatisfaction, and internalisation of sociocultural messages, negatively associated with emotional eating, and indirectly associated with depression, and dieting attitudes and behaviour. Binge eating was directly and positively related to parent body size, emotional eating, depression, and body dissatisfaction, while indirect associations were found with size-related teasing experiences, internalisation of sociocultural messages, and dieting attitudes and behaviour. A direct relationship between body dissatisfaction and loss of control was also found. Some gender differences were detected. Multivariate analysis of variance also revealed that binge eaters scored significantly higher on measures of depression, size-related teasing experiences, internalisation of sociocultural messages, and angry and worried related emotional eating than non-binge eaters. Differences were also found for participants reporting the presence or absence of overeating (regardless of loss of control) and loss of control (regardless of overeating). Overall, the study demonstrated that psychological and psychosocial factors have a significant association with both weight and binge eating behaviour in a non-clinical sample of preadolescent Australian school children. As such, future intervention programs may benefit by addressing these factors. In addition, these results support the idea of working toward the prevention of obesity and eating disorders simultaneously in children, and of extending research in this area to examine causality.