The specific problem examined by this study was that it is unknown if and to what extent there is a relationship between mathematics teachers' attitudes towards inclusion of students with learning disabilities in math and teachers' attitudes towards using evidence-based practices to improve mathematics achievement for this population. Therefore, this quantitative nonexperimental correlational study aimed to measure if and to what extent there is a relationship between mathematics teachers' attitudes towards the inclusion of students with learning disabilities in math classrooms and their attitudes towards using evidence-based practices for improving mathematics achievement. Eagly and Chaiken's (1993) theory of the advantages of an inclusive definition of attitude was the guiding theoretical framework for this study. An online survey instrument was used to gather data from K-12 mathematics teachers. The Spearman correlation coefficient analysis showed that teachers' attitudes, teachers' use of evidence-based practices, and teachers' willingness to provide classroom instructional accommodations to students with learning disabilities in inclusive classrooms were not significant predictors for improving mathematics achievement. The Spearman's rho correlations matrix showed attitude correlation coefficient (1.000), willingness (-0.011), Teacher Efficacy for Inclusive Practices (TEIP) (-0.360), and The Survey of Effective Classroom Management Strategies SECM (-0.336). There was no relationship between (Attitude), (willingness), (TEIP), and (SECM). This contrasted with previous research that concluded a relationship between professional development and implementation of evidence-based practices from teacher self-efficacy initiatives related to positive instructional practices. In addition, there are differences in how both general and special education teachers perceive inclusive settings (Leandres-Vaughn, 2017). The results also contrasted with current research, which indicated that students often perform toward the expectations of their teachers (Marita et al., 2019). Recommendations for future research included focusing on further investigation of critical variables related to attitudes, and willingness variables to support students' use of evidence-based practices should be unrelenting. Observation of teachers could also evaluate teacher self-reported scores, requiring qualitative inquiry to yield a more significant explanation of the study. [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.]