The United States is falling behind other nations in science and math, and many school systems are apprehensive toward adopting a mathematics reform instructional method because of teachers’ attitudes toward and implementation of the instructional method. The purpose of this quasi-experimental study was to examine the relationship between student achievement in mathematics, as measured by the Massachusetts Comprehensive Assessment System Eighth Grade Mathematics Assessment, and teachers’ use of reform, moderate, or traditional instructional strategies, as measured by the MOSAIC II Teacher Survey, and student attitudes toward reform instructional methods. Constructivism and social cognitive theory form the theoretical framework for the study. Five hundred thirty Grade 8 students and 6 Grade 8 math teachers from a middle school in a suburb of Atlanta, Georgia, participated in the study. An ANOVA and Tukey’s Post Hoc analysis revealed a significant difference on student achievement between the reform instructional method and traditional instructional method, and between the moderate instructional method and the traditional instructional method. In addition, the ANOVA and Tukey’s Post Hoc revealed a significant difference in student achievement where students with a positive attitude outperformed students with a negative attitude, and students with a positive attitude outperformed students with a neutral attitude. This research may contribute to positive social change by facilitating the adoption of a more efficacious math instructional method, and contribute to the body of knowledge by examining the benefits of using the reform and moderate instructional method.