Background: Migrants from developing to developed countries rapidly develop more obesity than the host population. While the effects of socio-economic status on obesity are well established, the influence of cultural factors, including acculturation, is not known. Objective: To examine the association between acculturation and obesity and its risk factors among African migrant children in Australia. Design and participants: A cross-sectional study using a non-probability sample of 3-to 12-year-old sub-Saharan African migrant children. A bidimensional model of strength of affiliation with African and Australian cultures was used to divide the sample into four cultural orientations: traditional (African), assimilated (Australian), integrated (both) and marginalized (neither). Main outcome measures: Body mass index (BMI), leisure-time physical activity (PA) and sedentary behaviours (SBs) and energy density of food. Results: In all, 18.4% (95% confidence interval (CI): 14-23%) were overweight and 8.6% (95% CI: 6-12%) were obese. After adjustment for confounders, integrated (b ¼ 1.1; Po0.05) and marginalized (b ¼ 1.4; Po0.01) children had higher BMI than traditional children. However, integrated children had significantly higher time engaged in both PA (b ¼ 46.9, Po0.01) and SBs (b ¼ 43.0, Po0.05) than their traditional counterparts. In comparison with traditional children, assimilated children were more sedentary (b ¼ 57.5, Po0.01) while marginalization was associated with increased consumption of energy-dense foods (b ¼ 42.0, Po0.05). Conclusions: Maintenance of traditional orientation was associated with lower rates of obesity and SBs. Health promotion programs and frameworks need to be rooted in traditional values and habits to maintain and reinforce traditional dietary and PA habits, as well as identify the marginalized clusters and address their needs.