A study was conducted to determine if an intervention could change social support and social-ecological resources of post-menopausal women diagnosed with type 2 diabetes, and if those changes mediated the intervention's effects on health behaviors and outcomes. Women (N = 279) were randomly assigned to receive a comprehensive 6-month Mediterranean Lifestyle Program (MLP) or usual care from their physicians (UC). MLP was successful in changing social embeddedness and social-ecological resources, but not a measure of perceived support. Changes in social-ecological resources mediated intervention effects on fat consumption, exercise and glycemic control. The experimental manipulation of mediators and the demonstrated mediation effects support the conclusion that social-ecological resources can contribute to improvements in healthful lifestyles for women with type 2 diabetes.