The transitional period between elementary and middle school remains an area of concern for educators. Many middle schools are plagued with retention issues, core class failures, increased discipline problems, and decreased attendance rates among students during their transitional period. The issues increase for students labeled as at-risk (McDougall & Hymel, 1998). The purpose of this study was to assess the effect of the middle school transition on Developmental Asset (DA) attainment, decline, or retention. This study employed quantitative, non-experimental, "ex post facto" research design. Secondary aggregated data from two elementary schools and two middle schools in one large urban school district were used to study the independent variables of the eight Internal Developmental Assets (IDA) scales, External Developmental Assets (EDA) scales, and the five social context scales (Scales, 1999). Five main hypotheses guided the study each with 16 subsidiary hypotheses. For hypothesis 1 and all associated subsidiary hypotheses, the researcher compared each students' scale score results on the Spring 2009 administration of the Developmental Asset Profile (DAP) to the Fall 2009 administration of the DAP For data analysis, the researcher performed paired sample "t"-test for each hypothesis. For hypotheses 2-4 and all associated subsidiary hypotheses, the researcher performed independent sample "t"-tests. The researcher calculated the Pearson's "r" correlation coefficient to test the relationship between academic achievement and the Developmental Assets for hypothesis 5 and all associated subsidiary hypotheses. No statistically significant change in the Total Developmental Asset scale scores for the Spring 2009 administration of the DAP scale scores for the Fall 2009 administration of the DAP for students transitioning from elementary to middle school was found. The students' assets declined in academic achievement, self-esteem, interest in school, and level of motivation and increased in psychological distress. No significant difference was observed between males and females nor any between at-risk and non at-risk students in regard to the Total Developmental Asset scale scores decreasing or increasing during the transition period between elementary and middle school. With both sets of groups, some of the subgroups showed significance. While no significant change in the Total Developmental Asset scale scores for students transitioning from elementary to middle school between grades five and six and those transitioning to middle school between grades six and seven were observed, the data revealed many significant the subgroup changes. Significant asset decline occurred in a number of the subgroups for students who transitioned to middle school between grades six and seven. Results for hypothesis 5 and all associated subsidiary hypotheses yielded positive correlations for the Total Developmental Asset Scale Scores and all 15 subgroups with academic achievement. Recommendations for practice and further researcher are made in Chapter 5. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]