Decreased academic achievement of middle school students is occurring due to educators' inability or reluctance to differentiate instruction and the barriers that impede or prevent its use. The purpose of this qualitative single-case study was to explore strategies for implementing differentiated instruction in the classroom and overcoming obstacles that may hinder its use. The conceptual framework was based on Tomlinson's model of differentiation and Vygotsky's zone of proximal development. Individual interviews and a focus group were used to collect data for this study. The study sample consisted of ten middle school teachers from a specific county in South Carolina. Three research questions were developed for this study. RQ1: What are educators' perceptions of differentiated instructional strategies used in South Carolina middle school classrooms? RQ2: What barriers exist for teachers when implementing differentiated instruction? RQ3: How can educators best implement differentiated instruction to improve academic achievement in a middle school classroom? Four emergent themes include (a) differentiating instruction in the middle school classroom, (b) individualized learning, (c) lack of resources, and (d) differentiated instructional best practices. The study's results provided insight for educators and administrators as to the range of differentiated instructional practices used in the middle school classroom, how they were used, and barriers that prevent differentiated instruction. The consistent application of differentiation to instruction varied in the study sample. The researcher recommends that institutions of higher learning develop curricula tailored to instruct pre-service educators to implement differentiated instructional strategies consistently. All educators should receive specialized differentiated instructional professional development to provide educational needs to an increasingly diverse 21st-century student population. [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.]