BackgroundTooth decay and periodontal diseases are the main oral pathologies in the world. The prevalence of overweight in children has increased worldwide. Overweight children have alterations in the composition of saliva and excessive consumption of saturated fatty acids tend to slow the metabolism of carbohydrates in the oral cavity leading to tooth decay, periodontal disease and others oral disorders. The aim of this study was to assess the relationship between oral pathologies and overweight in pupils of primary schools of Cameroon.MethodsA cross-sectional study was carried out from June to August 2020 in four government primary schools selected through cluster sampling in Yaounde. 650 pupils aged between 6 and 11 years were enrolled. Data collected included anthropometric, oral pathologies, quality of oral hygiene and feeding habits. Data were analysed with the SPSS 26.0 statistical software and binary logistic regression was used to determine the risks of oral pathologies in overweight pupils. P-value of 0.05 was considered statistically significant.ResultsThe prevalence of overweight was 27% (95% CI: 23.5—30.5). The main oral pathologies was tooth decay (60.3%). Binary logistic regression revealed that overweight pupils were significantly 1.5 times more likely to develop tooth decay than non-overweight pupils (95% CI: 1.1—2.4).ConclusionOverweight, tooth decay are prevalent among pupils. Overweight pupils have a higher risk of developing tooth decay compared to non-obese pupils. An integrated package of oral and nutritional health promotion activities is necessary in primary schools in Cameroon.