While mathematics achievement continues to decline across the United States, minimal research has been conducted on the use of CT skills to increase proficiency. This explanatory, nonexperimental quantitative study focused on the self-assessment of teachers' content knowledge in computational thinking skills and the relationship to students' achievement in mathematics. Using the Computational Thinking Scales Assessment, this study explored teachers' self-assessment in creativity, algorithmic thinking, cooperativity, critical thinking, and problem solving and the relationship to PSSA mathematics proficiency, including open-ended scores. The data was analyzed using descriptive and inferential statistics, including analysis of variance. The findings suggest that there is a relationship between teachers' computational thinking skills self-assessment and student mathematics achievement in PSSA mathematics proficiency and open-ended scores. There was a significance noted specifically in the CT skills of problem-solving and cooperativity. Using the TPCK framework, teacher content knowledge in CT skills aligned with pedagogical and technical knowledge may have an impact on increasing overall student mathematics achievement. [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.]