Examining how teachers' beliefs and behaviors predict students' motivation and achievement outcomes in physical education is an area of increasing research interest. Guided by the expectancy-value model and self-determination theory, the major purpose of this study was to examine the predictive strength of teachers' autonomy, competence, and relatedness support toward students' expectancy-related beliefs, subjective task values, concentration, and persistence/effort in physical education. Participants were 273 middle school students (143 girls, 130 boys) enrolled in a southeastern suburban public school. They completed previously validated questionnaires assessing their perceived teachers' support for autonomy, competence, and relatedness, expectancy-related beliefs, subjective task values, concentration, and self-reported persistence/effort during their regular classes. The results highlight the importance of teachers' competence support and autonomy support in fostering students' motivational constructs and achievement outcomes in physical education. The findings demonstrate that a supportive environment and high levels of expectancy-related beliefs and subjective task values are positively associated with students' achievement outcomes in physical education. (Contains 3 tables.)