Latinas are the largest, fastest growing female ethnic minority group in the USA, and also report the lowest levels of physical activity. Following the framework of the social ecological model, this review examines unique social and environmental factors that influence physical activity in Latinas. Research shows that Latinas receive little social support for activity despite having large, close-knit social networks. Interventions incorporating social support components are generally efficacious. Latinas also face many environmental barriers, including crime, heat, traffic, lack of facilities and a fear of immigration enforcement, and there have been few attempts to address environmental barriers in Latino communities. Successful future interventions will need to consider unique social and environmental barriers affecting Latinas, and help Latinas learn to incorporate social networks into physical activity participation.