This article discusses the relevance of systems thinking and engineering to project management, and the importance of appropriate selection of project management application systems. It identifies different systems thinking tools and techniques, and how project management application systems can lead to effective knowledge management and decision making. The article also compares and contrasts the advantages and disadvantages of different manual and electronic project, program and portfolio (PPPM) application systems within each PPPM knowledge area over the life cycle of a project, program or portfolio. Finally, it proposes appropriate PPPM application systems to support successful project, program and portfolio execution in different industry domains, and discusses contemporary developments in the use of project, program and portfolio (PPPM) application systems.