Using self-determination theory as a guiding framework, this study analyzed the impact of the Sport Education Model in self-determination and motivation, psychological basic need thwarting, enjoyment-satisfaction, boredom, and intention to be physically active in Physical Education (PE) of secondary school students in Spain. Two groups were selected for the study: an experimental group (EG; n=43), which received 19 volleyball lessons following the Sport Education Model, and a control group (CG; n=43), which received 19 traditional Physical Education lessons. Pre- and post-intervention measures were taken in both groups. The results showed significant improvements in intrinsic motivation in EG. The results are discussed, and the suitability of the Sport Education Model to improve self-determined behaviors in Physical Education is emphasized.