This paper explores school sports facility provision, physical education allocation and opportunities for physical activity and their association with the number of days adolescent girls participate in at least 60 min of moderate-vigorous physical activity per week (MVPAdays). Data were collected through self-administered questionnaires from Scottish secondary school girls (n = 1978) and head teachers (n = 123) participating in the Health Behaviour in School-aged Children 2005/06 study. The best predictor of adolescent girls' MVPAdays was hours allocated to PE in fourth year of secondary school ([beta] = 0.27, 95% CI 0.06-0.48). Having shower facilities resulted in decreased MVPA ([beta] = -0.51, CI -0.90 to -0.12), as did providing less than two team sports clubs ([beta] = -0.69, CI -1.28 to -0.10), compared with schools who provided four or more. Compared with schools with no after school clubs, girls who attended schools with activities at least 1 day per week were likely to have increased MVPAdays. PE allocation and extra-curricular clubs are likely to be of greater importance to girls' participation than school facilities per se. This study demonstrates how schools can maximize their environment to increase girls' PA and offers encouraging findings for those with limited sports facilities.