The present study examined age-group differences in students' self-reports of metacognitive activity in physical education settings. Five hundred and ten students of public elementary, junior and senior high school provided self-reports concerning the metacognitive processes they use during physical education lessons, their goal orientations and motivational climate of their class. The results showed that younger students reported more frequent use of metacognitive processes scoring higher in scales assessing task-orientation and perception of a task-involving motivational climate. The differences in metacognitive activity between the three age-groups were examined using task-orientation, and task-involving motivational climate as covariates in a multivariate analysis of covariance. The results revealed that task-orientation and task-involving motivational climate had a significant impact on students' self-reported metacognitive activity in physical education classes. All results are discussed in relation to achievement goal theory. (Contains 4 tables.)