The central purposes of this study were to determine the impact of high school transition on the experience of the 93 participating students (33 males, 60 females, 72 Caucasian, 17 African-American, 2 Asian, and 2 mixed-race) with respect to perceived changes in context (i.e. teacher support, teacher values) and self-processes (i.e. concerns regarding competence, relatedness and autonomy, hassles and uplifts) and changes in engagement (i.e. interest, effort, learning and performance goals) and outcome (GPA) across the transition to ninth grade, and to identify concerns about the transition to high school held by students at the conclusion of eighth grade and of ninth grade. This study also explores whether these variables differ for high and low performing students in eighth and in ninth grade. Based on Connell and Wellborn's (1991) model of self-systems, findings suggest that: participants perceived their eighth grade teachers as having placed higher value on their work and of holding higher expectations for students' academic achievement than their ninth grade teachers, participants reported expending more effort to pay attention in class and to pursue performance goals, as well as experiencing fewer competence-related hassles as eighth graders than as ninth graders. High achieving eighth grade students reported greater interest their classes, fewer relatedness hassles, more total uplifts, greater effort to do well in class, higher perceptions of their teachers' expectations for academic success, and feeling more supported by their teachers than did low achieving eighth graders. High achieving ninth grade students reported significantly fewer overall hassles and relatedness hassles than their low achieving counterparts. Students did not suffer a significant decline in GPA from eighth to ninth grades. Connell and Wellborn's identification of competence, relatedness, and autonomy as three essential psychological needs requiring satisfaction for students' success in the school context were reflected in that almost all of eighth graders' and ninth graders' transition-related concerns could be reliably categorized in accordance with their model. Implications of findings with respect to students' high school transition experience, as well as implications for schools' transition-related practices are discussed.