Self-concept can be understood as a person's evaluation of him or herself. It provides an estimate of a person's sense of self and emotional well-being (Haager & Vaughn, 1997). Self-concept is considered an important construct to understand for several reasons. First, it is often viewed as the "window" to a person's happiness and self-satisfaction. We consider individuals with a high self-concept as well adjusted and self-satisfied, whereas those with low self-concept are troubled and in need of support. Furthermore, low self-concept is associated with many negative outcomes including delinquency and drug use (Harter, 1993; Jung, 1994; Kaplan, Martin, & Johnson, 1986), depression (Parker & Asher, 1987), low peer acceptance (Li, 1985; Vaughn, Mcintosh, & Spencer-Rowe, 1991), and longterm unhappiness (Bednar, Wells, & Peterson, 1989; Harter, 1993). Thus, there are lots of reasons to consider self-concept an important outcome measure, particularly for students with significant learning problems.