The present two-wave longitudinal study examined the extent to which physical education (PE) teachers' democratic and socially supportive behavior, pupils' goal orientations, and the perceived motivational climate in PE explained differences in pupils' intended helping behavior by gender in PE classes. The results of 105 boys and 109 girls based on structural equation modeling revealed at both time points that the PE teachers' democratic and socially supportive behavior was positively related to pupils' concurrent perceptions of the motivational climate as task-involving as well as their higher concurrent intended helping behavior in PE. Pupils' prior perceptions of the motivational climate of PE as ego-involving were negatively related to their later perceptions of their PE teacher as behaving democratically and socially supportively. The study variables explained 50% (in boys) and 77% (in girls) of the variance of intended helping behavior at Time 2. (Contains 1 figure and 2 tables.)