This quantitative study aimed to explore the correlations between school teachers' cultural knowledge, teaching skills, and impact on the academic achievement of their students in the Southeast United States. The Multicultural Teaching Competence Scale (MTCS) was used as the test instrument to measure teachers' overall competence, cultural knowledge, and teaching skills. Early works of cultural competence focused on acknowledging cultural diversity in the classrooms through curriculum. The study noted a wide achievement gap representing culturally diverse students in public schools across the United States. Researchers reported a need to investigate educators' duty to understand cultural backgrounds other than their own. The MTCS's 16 items were created and reviewed by experts. A pilot study of 506 pre-and in-service teachers was conducted initially for the validity and reliability of the instrument. Exploratory factor analysis results suggested that a 16-item, two-factor model was a good fit for the data and superior to competing models. In the data analysis of this research, a Pearson's correlation resulted in a correlation coefficient (r) equaling -0.219, indicating a strong negative correlation, which can be assessed as a relationship, and p < 0.019 meaning that the coefficient has a significant difference from zero. The findings for teachers' cultural knowledge and student achievement scores are counterintuitive, suggesting there is a need for factual evidence and additional factors for cultural knowledge compared with the MTCS, which might improve the understanding of the counterintuitive results. [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://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]