Individual socioeconomic status is linked to obesity risk, though, less is known about the influence of an area's socio-environmental conditions on obesity/overweight prevalence. This association was investigated using obesity/overweight data collected from 2445 individuals in Athens greater area, who were randomly enrolled in ATTICA study, during 2001 to 2002, and factors related to educational and economic level, population density, immigrants and green urban areas. Thematic mapping illustrated the socio-environmental status and highlighted the obesity/overweight prevalence across the municipalities of Athens. Global statistical models revealed that high socio-environmental status, educational and economic level were inversely associated with obesity/overweight (p < 0.001). Furthermore, local Geographically Weighted Regression revealed spatial non-stationarity in the relationship between green urban areas and obesity/overweight. The findings of the study lead to the better understanding of the factors affecting obesity/overweight and may support the development of policies that target to well-being, decrease of obesity/overweight prevalence and improvement of public health.