This study aims to focus on the basic components of computational thinking (CT) and to investigate its relationship with competencies/skills in the 21st century and establish new relationships in the context of developing computational thinking in the educational environments. Based on this approach, in the first stage, definitions of computing, computational theory, computational science and engineering (CSE), and mathematical sciences are given, emphasizing the place and importance of CT in the literature, and their relationships between CT are investigated. In the second stage, the difficulties encountered in the development of computational thinking are mentioned and explanations are made about the development of CT. In this context, the approaches proposed for the development of CT through pedagogical and technological pedagogical content knowledge are explained with discussions and examples are given. With this study, the conceptual framework of the development of CT and its relations with 21st-century competencies are established.