This study explored the problem of increasing vocabulary through peer tutoring at the primary level. It sought to determine whether greater opportunity to learn can be provide through peer tutoring by untrained primary grade tutors or untrained upper grade tutors. The effects of tutoring on sight word gains of receivers versus non-tutored controls were compared. The effects of tutoring versus non-tutoring on sight word gains of primary tutors were examined. Fifteen sessions of twenty minutes instructional time each were provided. During this time, the Dolch Basic Sight Words were taught. The primary grade tutors and the upper grade tutors were found to be alike in effectiveness, instructional behaviors, and amount of time used in teaching a word; tutoring by either primary or upper grade tutors was superior to non-tutoring; and tutoring had no noticeable effect on sight word gains of primary tutors. (Author/MKM)