The objective of this research was to determine the project constraints that must be considered to ensure project success in a typical manufacturing environment like a pulp and paper plant. The research methodology used to answer the research questions was a mixed –method approach.  The modes of data collection were literature study, case studies and a survey questionnaire.  The data was analysed using between-methods triangulation. The research presented was limited to data obtained within the South African Pulp and Paper Industry.  The research will give project managers, and anyone involved in execution of projects in a Pulp and Paper plant environment more insight and better understanding of which constraints to consider to ensure better project success rates. The research concluded that Triple constraints are not the only determinants of project success in the Pulp and Paper plant.  Additional project constraints were identified were; Risk; Human resource management; Legal requirements; Technical performance