Galectin-1, a recently identified peptide, is primarily released from the adipose tissue. Although galectin-1 was shown to have an anti-inflammatory effect, its specific function is not clearly understood. We aimed to evaluate the relationship of serum galectin-1 levels with clinical and laboratory parameters in childhood obesity. A total of 45 obese children (mean age: 12.1 ± 3.1 years) and 35 normal-weight children (mean age: 11.8 ± 2.2 years) were enrolled. Clinical [body mass index (BMI), waist circumference (WC), percentage of body fat and blood pressure] and biochemical [glucose, insulin, lipids, galectin-1, high-sensitive C-reactive protein (hsCRP) and leptin levels] parameters were assessed. Serum galectin-1, hsCRP and leptin levels were significantly higher in obese children than those in normal-weight children (12.4 vs 10.2 ng/mL, p < 0.001; 3.28 vs 0.63 mg/L, p < 0.001; 8.3 vs 1.2 ng/mL, p < 0.001, respectively). In obese children, galectin-1 levels correlated negatively with fasting glucose (r = −0.346, p = 0.020) and positively with fat mass (r = 0.326, p = 0.026) and WC standard deviation score (SDS) (r = 0.451, p = 0.002). The multivariate regression analysis demonstrated that serum galectin-1 levels were significantly associated with fasting glucose and WC SDS. This study showed that obese children had significantly higher galectin-1 levels in proportion to fat mass in obese cases than those in healthy children, which may be interpreted as a compensatory increase in an attempt to improve glucose metabolism.