Multiage programming is a school reform option used throughout the United States. Much of the current literature focuses on the short-term benefits of multiage programs, particularly at the elementary level, with little consideration for long-term effects or for what might happen to students once they leave the multiage classroom and enter middle school. While there has been significant research that generalizes the transition experience of the general population of students, there has been limited research conducted on this transition experience for this specific population, the multiage elementary student. The purpose of this simultaneous, mixed methods study was to provide an in-depth examination of the transition effects on students who transition from multiage elementary classrooms to traditional single-grade classrooms at the middle school. In this study, eight students who had previously attended multiage elementary classrooms were given the Piers-Harris 2 Children's Self Concept Scale at three points, fall, winter, and spring during their first year in middle school to assess the students' social and emotional well-being during the transition. Students were also administered a middle school transition questionnaire to identify what procedural, academic, or social issues were of concern to them. Students were interviewed about their transitional experiences. In the analysis of the data showed that the students' overall sense of self and self-esteem improved over the course of the transitional year. Student concerns with procedures, academics, and social life decreased over the course of the year. The following major categories emerged from the interviews: (a) adjusting to the structure of middle school, (b) adjusting to new academic demands, (c) managing relationships with teachers and peers, and (d) changing sense of self. The findings have implications for middle level educators, multiage classroom elementary educators and for parents. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]