The purpose of this study was to identify the psychosocial, environmental and behavioral factors associated with calcium intake, physical activity and bone health in a cohort of adolescent girls. Baseline data (N = 718 girls, mean age: 11.6 plus or minus 0.4 years) from the Incorporating More Physical Activity and Calcium in Teens (IMPACT) study conducted in Texas, 2001-03, were utilized for the analyses. Hierarchical linear regression was used to examine the associations of interest. Confounders adjusted for included ethnicity, menarchal status, body mass index and lactose intolerance. Several psychosocial and behavioral factors were significantly associated with bone quality. These included knowledge of calcium content of foods (beta = 0.08, P = 0.016), self-efficacy toward consuming calcium-rich foods (beta = 0.16, P = 0.047), physical activity self-efficacy (beta = 0.20, P = 0.002), physical activity outcome expectations (beta = 0.5, P = 0.004), family encouragement to do physical activity (beta = 0.96, P = 0.027), friend engagement in physical activity (beta = 1.3, P = 0.001) and participation in sports teams (beta = 1.7, P less than 0.001). Self-efficacy, social support and participation in sports teams appear to be strongly associated with bone health in adolescent girls. Future health education/health promotion programs need to address these factors for effective primary prevention of osteoporosis in this population. (Contains 5 tables.)