Using Self Determination as a framework, the purpose of the study was to examine the relationships between basic psychological needs, motivational regulations, self-esteem, subjective vitality, and social physique anxiety in physical education. One thousand and eighty two high school students aged between 14 and 19 [mean (M) = 15.89 ± 0.95 years] from six public high schools participated to the study. Students' basic psychological needs: motivational regulations, subjective vitality and self-esteem served as positive indicators, while social physique anxiety was a negative indicator of psychological well-being. Structural equation modelling results revealed that students' motivational regulations mediated the relationship between basic psychological needs and psychological well-being. Intrinsic motivation negatively predicted social physique anxiety and positively predicted subjective vitality. Amotivation positively predicted social physique anxiety and negatively predicted subjective vitality. Identified regulation and external regulation positively predicted subjective vitality. Results supported the tenets of Self Determination Theory (SDT) and suggested that satisfying adolescents' basic psychological needs in physical education will promote their psychological well-being.