Examined age and gender differences in the quality of sport friendship, noting relationships between friendship quality and motivation-related variables and reexamining the validity of the Sport Friendship Quality Scale (SFQS). Adolescent tennis players completed the SFQS and other measures. Age and gender differences in friendship emerged. Companionship and pleasant play, conflict resolution, and things in common predicted higher tennis enjoyment and commitment. Results supported the validity of the SFQS. (SM)