Causal relationships among perceived motivational climates in physical education classes, goal orientations, and “Zest for Living” were investigated reciprocally in junior high school students. This longitudinal study involved 1045 junior high school students (mean age = 13.9±0.8 years) who completed questionnaires on 5 occasions at 2-month intervals throughout the academic year. The measures used included a questionnaire on motivational climates in physical education (mastery climate, cooperative climate, and performance climate), a scale assessing goal orientations (student task orientation and student ego orientation), and a scale assessing Zest for Living. The validity of the 5-wave cross-lagged effect model was verified using structural equation modeling. The results of the study suggested the following processes: (1) The mastery climate and cooperative climate had positive causal effects on Zest for Living. (2) The mastery climate and cooperative climate had positive causal effects on Zest for Living through mediation of task orientation, and exhibited a positive cycle. (3) The performance climate had positive causal effects on ego orientation, but negative causal effects on task orientation. In conclusion, to enhance Zest for Living in junior high school students, it is important for teachers to cultivate a mastery climate and cooperation climate in physical education classes. In addition, the performance climate in physical education classes has an indirect negative impact on Zest for Living.