This study assessed ethnic and gender differences in ideal body size, body dissatisfaction (BD), and the relationship between BD and various predictors (e.g., body composition indicators and cardiorespiratory fitness). The sample consisted of 190 White and Hispanic preadolescents aged 10–13 years. Demographic, percent body fat (%BF), body mass index (BMI), body image variables, and cardiorespiratory fitness (CRF) were examined. A significant Gender × Ethnicity interaction was found for ideal body size (p < .05), with Hispanic girls preferring the thinnest figures and Hispanic boys the largest figures, compared to their counterparts. No significant gender or ethnic differences in BD were observed. After controlling for demographic and cultural variables, increased %BF and BMI scores predicted greater BD, whereas CRF did not.