Abstract Objective To examine differences in overweight and obesity of second-generation Turkish, Moroccan and Surinamese migrants v . first-generation migrants and the ethnic Dutch. We also studied the influence of sociodemographic factors on this association. Design Data were collected in 2008 in a cross-sectional postal and online health survey. Setting Four major Dutch cities. Subjects In the survey 42 686 residents aged 16 years and over participated. Data from Dutch ( n 3615) and second/first-generation Surinamese ( n 230/139), Turkish ( n 203/241) and Moroccan ( n 172/187) participants aged 16–34 years were analysed using logistic regression with overweight (BMI ≥ 25·0 kg/m 2 ) and obesity (BMI ≥ 30·0 kg/m 2 ) as dependent variables. BMI was calculated from self-reported body height and weight. Sociodemographic variables included sex, age, marital status, educational level, employment status and financial situation. Results After controlling for age, overweight (including obesity) was more prevalent in most second-generation migrant subgroups compared with the Dutch population, except for Moroccan men. Obesity rates among second-generation migrant men were similar to those among the Dutch. Second-generation migrant women were more often obese than Dutch women. Ethnic differences were partly explained by the lower educational level of second-generation migrants. Differences in overweight between second- and first-generation migrants were only found among Moroccan and Surinamese men. Conclusions We did not find a converging trend for the overweight and obesity prevalence from second-generation migrants towards the Dutch host population. Therefore, preventive interventions should also focus on second-generation migrants to stop the obesity epidemic.