Research has shown that computational thinking and kindergarten mathematics instruction can be integrated; however, evidence of how specific mathematical knowledge relates to computational thinking remains scarce. Additionally, we do not know if and how children's mathematical knowledge co-occurs with computational thinking and how these knowledges relate to students' performance on computational thinking assessments. This qualitative study sought to fill this knowledge gap by examining the following research questions through a joint embodied cognition and enactivist lens: (1) How are kindergarten students' mathematical knowledge (MK) and computational thinking (CT) operationalized during a CT assessment? In what ways, if any, do MK and CT co-occur, and (2) How do students' mathematical knowledge and co-occurring mathematical knowledge and computational thinking relate to their performance on individual assessment items? Using a dataset collected for a larger research study (NSF project award #DRL-1842116), I analyzed video of 60 kindergarten students engaging with 14 items in an interview-based, computational thinking assessment. I coded and memoed the data to operationalize how students demonstrate mathematical knowledge and computational thinking, then analyzed the coded data to identify co-occurring knowledge. Lastly, I developed case studies to describe how students' knowledge related to their assessment item performance. Results indicate that students demonstrate varying levels of mathematical knowledge and computational thinking multi-modally through their gestures, language, and actions with the assessment materials. Students' spatial and unit measurement knowledge most frequently co-occurred with computational thinking, occurring most often when students built and read/enacted programs. These co-occurrences were categorized as independent or dependent, depending on the nature of their relationship to the computational thinking outcomes. These findings illustrate the intricate connections between mathematical knowledge and computational thinking and that students' mathematical knowledge relates to their performance on computational thinking tasks. These findings have implications for computational thinking curriculum and assessment design, mathematics curriculum design, and theory. Based on the results of this present study, I recommend that mathematics curriculum developers leverage the spatial and unit measurement connections in computational thinking tasks to design experiences for children to grow their spatial reasoning and measurement knowledge. [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.]