Evidence of associations between psychopathology and obesity in childhood remains inconsistent, and most studies have been conducted in Western countries. This study investigated psychological and physiological correlates of obesity in a community sample of children in Taiwan. In total, 302 children (157 overweight/obese and 145 healthy-weight children) were selected from first- and fourth-grade schoolchildren in eight elementary schools in 2009. These children participated in a comprehensive health examination, including a physical examination, blood sample analysis, and questionnaire administration. We found that regarding physiological characteristics, compared with the healthy-weight children, the overweight/obese children had significantly higher values for body fat estimated using the bioelectrical impedance method (p < 0.001), systolic blood pressure (p < 0.001), and diastolic blood pressure (p = 0.001); lower values for high-density lipoprotein (p < 0.001); and worse values for glutamic-pyruvic transaminase (p < 0.001), triglycerides (p < 0.001), and fasting blood glucose (p = 0.049). In logistic models adjusted for parental and child traits and physiological characteristics, children's overweight/obesity was significantly associated with lower self-concept (odds ratio [OR] = 0.96, 95% confidence interval [CI] = 0.93-0.99) and less disruptive behavior (OR = 0.96, 95% CI = 0.92-0.99). Less disruptive behavior and the lack of a higher prevalence of anxiety and depression in childhood obesity appear to be a unique pattern in Taiwan that warrants further investigation.