The purpose of this study was to examine the relationship between motivational climate and goal orientation in achievement goal theory on the one hand and attitude toward physical education classes on the other.   We used the following hypothetical model: The presence of two motivational climates (performance and mastery) in physical education classes promotes goal orientation (ego and task), which in turn increases the positivity of students toward physical education classes. The validity of this model was verified using simultaneous multi-population analysis.   The sample comprised 1263 junior high school students (mean age=13.2±0.9 years). The measures employed were a questionnaire to investigate motivational climate in physical education, a scale assessing goal orientation, and a scale measuring positivity toward physical education classes.   The simultaneous multi-population analysis demonstrated the validity of the hypothesized model for both boys and girls. All significant paths in the model had positive values. Furthermore, we identified three processes: (1) The mastery climate had a positive influence on students' task orientation, which in turn had a positive influence on attitude toward physical education classes. (2) The mastery climate had a direct positive influence on attitude toward physical education classes. (3) The performance climate had a positive influence on students' ego orientation, which in turn had a positive influence on their attitude toward physical education classes.   The analysis showed that in both groups, the presence of a mastery climate had a direct positive influence on attitude toward physical education classes. In addition, the presence of a performance climate indirectly promoted a positive attitude toward physical education classes through ego orientation.   In conclusion, to enhance a positive attitude toward physical education, it is important for teachers to enhance not only the mastery climate but also the performance climate in their classes.