Systematically applied W. R. Jenson's (1990, unpublished; see also G. Rhode et al, 1992) Mystery Motivator (MM) across 9 Ss (5 3rd-grade boys and 4 5th-grade boys) from 2 classrooms. All Ss were experiencing significant difficulties completing and turning in their homework assignments. The MM was devised to treat a variety of behavioral and academic problems in clinical practice. It combines 2 key treatment components: immediate performance feedback and intermittent reinforcement. Materials include a weekly chart, erasable pens, and a reward menu. Results appear promising, suggesting that the MM is an effective, socially valid intervention that can be implemented in the classroom with integrity.