The present intervention study examined whether physical education (PE) teachers can learn to make use of autonomy-supportive and structuring teaching strategies. In a sample of 39 teachers (31 men, M = 38.51 ± 10.44 years) and 669 students (424 boys, M = 14.58 ± 1.92 years), we investigated whether a professional development training grounded in self-determination theory led to changes in (a) teachers' beliefs about the effectiveness and feasibility of autonomy-supportive and structuring strategies and (b) teachers' in-class reliance on these strategies, as rated by teachers, external observers, and students. The intervention led to positive changes in teachers' beliefs regarding both autonomy support and structure. As for teachers' actual teaching behavior, the intervention was successful in increasing autonomy support according to students and external observers, while resulting in positive changes in teacher-reported structure. Implications for professional development and recommendations for future research are discussed.