This study examined whether the provision of choice in physical education (PE) enhanced students' autonomous motivation, perceived autonomy support, and physical activity (PA) levels, relative to a "regular PE" control group. Students from eight intact high school PE classes ("N" = 257, M[subscript "age"] = 12.91) were randomly assigned to control (i.e., four classes) and intervention (i.e., four classes) conditions. Students in the intervention group were given a unique opportunity to choose their preferred participatory role in their PE units, while control students participated in normal teacher-led PE, and data were collected over a 15-week program (i.e., three units of five weeks each). The results indicated that a lack of choice in PE aligned with less positive perceptions of autonomy support among students within the control group, compared with their counterparts in the intervention group. In some choice formats, students exhibited significantly higher PA levels than students who undertook normal PE. These findings indicate that offering choice in high school PE lessons may encourage perceptions of autonomy support and levels of in-class physical activity. (Contains 3 tables.)