Insufficient teacher preparation, ineffective instructional methods, and cultural biases often lead to the misapplication of culturally responsive practices, exacerbating the educational opportunity gap between marginalized and nonmarginalized students. When schools do not address these issues of ineffective teaching and bias, marginalized students who feel isolated in their education continue to become disengaged and experience significant personal and educational problems. Despite the increasing enrollment of marginalized students within suburban school districts, the academic opportunity gap remains persistent due to educators' perceived preparation deficiency and lack of support for culturally responsive teaching practices. This explanatory sequential mixed methods study was grounded in Gay's (2002a) Culturally Responsive Framework. The study utilized a survey and interviews to examine predictive relationships between teachers' culturally responsive preparedness and practice levels of New Jersey high school teachers in a suburban setting. Sixty participants completed a survey based on Hsiao's (2015) CRTPS and Siwatu et al.'s (2015) CRCMSE scales, allowing a deeper understanding of a teacher's perceived usage of culturally responsive practices. Four interviews that expanded on the quantitative survey results and provided in-depth examples of culturally responsive practices in a current educational setting followed the quantitative survey phase. The quantitative analysis revealed that the formation of group belonging is the best predictor of a culturally responsive classroom with a standardized beta coefficient of 0.47 and curriculum and instruction is the poorest predictor with a standardized beta coefficient of 0.12. In addition, the interviews determined that exposure to diversity impacted a teacher's perceived preparation and ability to utilize culturally responsive practices. Educational collaborators must reevaluate pre-service programs, increase culturally supportive practices in the classroom, and work as a unit to create effective instructional methods that support marginalized learners and minimize discriminatory policies and procedures. Additional research is needed to explore further how a teacher's perceptions and abilities may differ concerning their use of culturally responsive practices and the role of exposure to diversity. [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.]