Background: Childhood overweight/obesity is becoming a threat to public health worldwide affecting both developed and developing countries. Information on the burden of childhood obesity and the factors associated with it is important in designing appropriate strategies for its prevention and control. Aim: This study was conducted to determine the prevalence and correlates of obesity among primary school pupils in Sokoto metropolis, Nigeria. Materials and Methods: A cross-sectional study was conducted among 240 primary school pupils selected by multistage sampling technique. Information on the participants’ socio-demographic characteristics, and their physical activity and dietary patterns were obtained with a set of structured interviewer-administered questionnaire; anthropometric assessment was also done for them. Data were analyzed using IBM SPSS version 23 statistical computer software package. Results: Forty-one (17.1%) of the 240 participants were obese, close to half of them (45.4%) had normal weight, about a third (31.3%) had thinness, while a few of them (6.3%) were overweight. Physical inactivity and unhealthy dietary behavior were also very prevalent among the participants. Obesity was significantly associated (p < 0.05) with the participants’ age, sex, socioeconomic status, physical inactivity and unhealthy dietary behavior. Conclusion: This study showed high prevalence of obesity, physical inactivity and unhealthy dietary behavior among primary school pupils in Sokoto metropolis, Nigeria. Government, policymakers and school administrators should design appropriate strategies for promoting healthy dietary behavior and physical activity among primary school pupils to halt the current trend.