To investigate the association between the neighbourhood social environment, including social cohesion, perceived neighbourhood safety, perceived neighbourhood violence, and obesity in Brazil.Cross-sectional study.6 state capitals in Brazil (Salvador, Vitoria, Belo Horizonte, Porto Alegre, Sao Paulo and Rio de Janeiro) PARTICIPANTS: Current or former employees of five federal universities and one research centre in each of the six Brazilian state capitals who were participants of the baseline wave (2008-2010) of the Brazilian Longitudinal Study of Adult Health (n=11 456; 56% women; 56% White, 28% Brown, and 16% Black).Obesity, based on measured weight and height, and defined as having a body mass index ≥30 kg/m.No associations were found between the neighbourhood social environment and obesity among men. In multilevel logistic regression models adjusted for age, education, skin colour, state of residence, and individual-level social cohesion and perceived violence scores, respectively, women living in the least socially cohesive neighbourhoods and in those perceived as most violent had higher odds of obesity compared with their counterparts (OR=1.25, 95% CI=1.02-1.53; OR=1.28, 95% CI=1.04-1.56, respectively). When stratified by neighbourhood socioeconomic status (SES)-defined based on number of people per household, proportion of children 0-4 years, median income and per cent of white residents at the neighbourhood level-results for social cohesion and for violence remained only for women residing in high SES and low SES neighbourhoods, respectively.In this civil-servant sample in six large cities in Brazil, the neighbourhood social environment was associated with obesity among women, but not men. Neighbourhood-level interventions to increase social cohesion and reduce violence may help in the prevention of obesity among women in Brazil.