<p>  </p> <p>This research study aims to explore the understanding and implementation of CT and its core concepts by CS High School teachers. This research study examined CS teachers' understanding of CT’s core concepts; a) decomposition, b) pattern recognition, c) abstraction and d) algorithm design. Furthermore, the study also explores how these CS teachers applied these core concepts to their instructional practice. </p> <p>The qualitative case study utilized the Pedagogical Content Knowledge (PCK) framework as a lens to explore the teachers’ understanding. For this qualitative research study, purposeful sampling was employed to recruit participants with specific knowledge or experience about a topic of interest. In-depth semi-structured interviews were performed with five CS high school teachers for data collection. The researcher used coding and thematic analysis to analyze the data. Teachers shared their understanding of CT, its core concepts, and how they incorporate these into their instructional practice.</p> <p>The findings in the study present the different understandings of the teachers regarding CT’s core concepts and how each of them applied such concepts through different pedagogical approaches to their instructional practice. The findings in the study could provide an opportunity for high school teachers to explore different understandings from other high school teachers and potentially provide collaborative opportunities. </p> <p>The research study concludes with two significant findings and their implications for the field of CS education. It also recommends other researchers and provides collaborative opportunities with other high schools. Moreover, this research contributes to and enriches the current literature on CT in education. </p>