This essay analyzes the concepts of systems thinking in project management, discussing various tools and techniques that aid project managers in solving project problems. It assesses the application of system engineering to project cases, highlighting how system thinking concepts and methodologies help project, program, and portfolio managers (PPPM) organize projects involving the “systems engineering body of knowledge (SEBoK)”. The paper emphasizes the importance of project management application systems for internal and external project objectives, leading to effective knowledge management and decision-making. It also discusses the advantages and disadvantages of manual and electronic project, program, and portfolio application systems, supporting successful project execution in various domains, and explores contemporary developments in their use. The relevance of system thinking for organizing complex projects is highlighted, emphasizing its role in improving project implementation and reducing problems. Real-world examples like the BP Texas City and Deepwater Horizon incidents are used to illustrate the importance of systems thinking in preventing and managing project-related disasters. The essay concludes by underscoring the best practices related to system thinking, such as defining project lifecycle milestones, requirements, and scope, ensuring quality work, and tracking progress.