Problem Statement: Algebra, which is one of the basic principles ofmathematical learning, still maintains its importance in mathematicsprogrammes. However, especially starting from the primary school years,algebra represents a complex mathematical factor in the operational stagefor many students. In this scope, a differentiated teaching approach thataccounts for personal differences within a class, considers differentstudents’ different skills and learning needs, and draws on students’strengths gains importance.Purpose of the Study: This study was done with the aim of determining theeffect of a differentiated teaching approach in sixth grade mathematicslessons in the algebraic learning field on students’ academic successes.Method: This study was designed according to equal status, sequenced,mixed methods research. The sixth grade students of a lowersocioeconomic level were chosen from a state secondary school in SaricamCounty in Adana. Fifty-seven randomly chosen students who were closeto each other in terms of gender distribution and first term final gradeformed the study group for the research. The research used the datacollection tools “Algebraic Success Test” and “Semi-Structured InterviewForm Regarding the Differentiated Teaching Approach,” which weredeveloped by the researcher. The quantitative data that were obtainedwere tested by covariance analysis, and the qualitative data were analyzedby content analysis. Findings and Results: At the end of study, it was revealed that the differentiated teaching approach in a sixth grade algebra lesson increases student success, and during this period, students showed positive cognitive and affective developments.Conclusion and Recommendations: In sum, based on the results, it evident that a differentiated teaching approach applied to sixth grade algebra lessons increases students’ academic success, and during this period, such an approach provides positive cognitive and affective developments. Since this study is limited in terms of student dimensions, more studies should be conducted on different subjects and at class levels in which teachers’ opinions about application stages can also be investigated. Additionally, this study examined multiple teaching methods of differentiated teaching. In future research, experimental studies regarding the application or comparison of different techniques can be pursued.Keywords: Algebra, primary school mathematics, differentiated teaching, mathematics achievement