A particularistic case study was designed to investigate how portfolio assessment contributed to teachers’ instructional decision-making. Four fifth grade teachers and twenty-four fifth grade students were selected as the participants for this case study. The dual role of teacher as instructional leader and assessor was examined. Data were collected from classroom and team observations, formal and informal interviews, document analysis, audiotapes, and team planning sessions. This study demonstrated the empowerment and autonomy that teachers developed during their experience with portfolio assessment. Teachers increased their authority related to instructional decision-making, initiating self and student change, and empowering students. Analyzing student writing samples and creating benchmarks inductively derived from their own students’ writing samples provided teachers with an active role in determining the instructional focus. Teachers increased their level of decision-making through collaborative idea sharing, brainstorming sessions, and peer encouragement. They transferred these skills to other areas. The change in teachers’ instructional practices was gradual and evolutionary. The decision-making processes that the teachers underwent were context dependent and were directly related to their analysis of student writing portfolios. The monthly portfolio assessment sessions served as the catalyst for change. Teachers developed instructional adaptations and modifications based upon specific areas of student need. This process resulted in changes in the following areas: instruction, assessment, attitude, student expectations, and philosophy. The integration between assessment and instruction resulted in authentically designed experiences for students. Gradually, teachers shifted their cognitive exploration techniques from concrete to abstract techniques. The expectations for decision-making also shifted from teacher ownership to student ownership. A socialization process emerged whereby students assumed more ownership and direction for their own learning. An integrated instructional/assessment system was developed for the students which paralleled the system that was created and used by the teachers. Students inductively derived their own benchmarks based upon their own writing. As a final step toward student empowerment, metacognitive strategies were utilized by having each student evaluate his own progress by providing both quantitative and qualitative documentation along with personal reflections and future writing goals. / Ed. D.