The aim in this study was to identify predictors of teachers' and students' motivation and autonomy support in physical education. Ninety-four physical education teachers (26 female, 68 male) and 2127 students (1093 boys, 1026 girls, and 8 no gender specified) from 56 (42 public, 14 private) high schools all voluntarily participated in the study. The students' perceived autonomy support, the intrinsic motivation for physical education and teachers' perceptions of their own autonomy support in lessons and their motivations to teach were assessed. Pearson correlation analysis showed no relationship between teachers' perceptions of autonomy support and the students' perceptions of autonomy support. Regression analysis showed that: a) the students' perceptions of autonomy support were positive predictors of the students' intrinsic motivations, b) the assessment support sub-dimension of autonomy support was positive predictor of teachers' intrinsic motivations to teach in physical education. Given these findings, it becomes critical that PE teachers learn about the value of autonomy support and how to provide it during pre-service and in-service teacher education.