Background/Aims: To evaluate the relationship of socioeconomic status (SES) and body mass index (BMI) with skeletal maturation in children from Marrakech (Morocco). Methods: SES, BMI z-score and bone age (BA) were measured in a cohort of 623 children (280 boys and 343 girls, chronological age (CA) ranged from 6.6 to 18.8 years, mean 14.1 years). BA estimation was performed with the Greulich and Pyle atlas. Two social groups (privileged and unfavorable SES) were defined. A multiple linear regression analysis was performed to assess the relationship between BA-CA and age-and sex-specific BMI z-score. Results: Global maturation delay was seen in the sample (BA-CA -0.56; SD 1.29). There was a significant relationship between skeletal maturation (BA-CA) and child BMI z-score among both genders. Bone age was more advanced in children with a greater BMI z-score. Privileged SES was positively associated with children's BA-CA for girls but there was no association for boys. In the boys' sample, there was no evidence that BA-CA variations with BMI z-score depended on socioeconomic status (p = 0.664). Whatever the gender of the child, a greater BMI z-score increases the maturation. Conclusion: The multiple linear regression analysis is an interesting approach to understand the links between skeletal maturation, BMI and SES. In Moroccan children, excess weight is associated with privileged SES.