Objectives To determine the prevalence and factors associated with overweight and obesity in Peruvian schoolchildren. Materials and Methods Cross-sectional study carried out between 2013 and 2014. The probabilistic, multistage stratified sampling included 1 191 conglomerates with 7 914 dwellings (4 842 in the urban area and 3 072 in the rural area) of Peru. A total of 2 801 schoolchildren aged between 5 and 13 years were evaluated. The Z score of the body mass index by age (ZBMI) was used according to the WHO. Overweight was considered (ZBMI> 1 and ≤2) and obesity (ZBMI >2). Results 18.1% of the sample was overweight and 14.1% were obese. Overweight predominated in males (18.7%), schoolchildren aged 8 to 10 years (19.6%), non-poor (21.2%), residing in the urban area (21.6%), from Metropolitan Lima (22.8%) and Costa (22.7%). The factors associated with overweight included non-poverty (OR=1.9), living in urban areas (OR=1.7), Metropolitan Lima (OR=1.9) and Costa (OR=1.6). On the other hand, factors associated with obesity included male sex (OR=3.1), secondaryeducation level of the head of the household (OR=1.8), higher education (OR=2.5), non-poor (OR=9.2), residing in an urban area (OR=3.4), Metropolitan Lima (OR=4.8) and Costa (OR=2.9). Conclusions The prevalence of obesity or overweight in schoolchildren is high. Non-poverty, living in urban areas, Metropolitan Lima and Costa are associated with overweight. Being a man, non-poor, the highest educational level of the head of the household, living in the urban area, Metropolitan Lima and Costa were associated with obesity.