The purpose of this research paper study is to determine if differentiated instruction has an effect on student achievement in the music classroom. The findings of this study were data collected to answer the following research questions: 1) Does differentiated instruction have an impact on student achievement? and 2) Are there components of differentiated instruction that have a greater impact on student achievement than others? When educators differentiate instruction strategically, they can better meet their students' learning needs while helping them make great strides in overall achievement. Differentiation not only recognizes that students are at different levels of readiness, but it also recognizes that students vary in their interests and how they process new information or skills (Tomlinson, 1999). Teachers differentiate instruction to make appropriate accommodations to ensure that the curriculum is engaging and appropriate for all learners. This paper provides a literature review, including a rationale for the practice of differentiation; the definition, characteristics, and theoretical background of differentiated instruction; ways to differentiate content, process, and product according to students' readiness levels, learning profiles, and interests; and a description of the few empirical studies that exist on the impact differentiated instruction has on student achievement. The findings in this study provide anecdotal evidence of student music proficiency growth and achievement as a result of implementation of differentiated instruction. The findings in answering the second research question also suggest that there were components of differentiated instruction that have greater impact on student achievement than others. It is the researcher's hope that the findings of this study will provide a foundation for future studies on the effects of differentiated instruction on academic achievement in the music classroom.