This study has investigated the relationship among the principles of Quality Management System to design a hierarchical implementation schema suitable for Ethiopian Plastic Industries. QMS principles are the fundamental truth or laws that form the basis of quality management. These principles have been identified to facilitate the achievement of quality objectives and form the foundation for effective quality management system implementation. The study carried out a detailed analysis of the existing problems associated with implementation of QMS; related literatures are reviewed and concisely organized in to related topics of the study. Questionnaire has been used to collect relevant data of QMS implementation in Ethiopian plastic industries. The questionnaire has been designed based on the findings from literature review and the basis of QMS principles. Interview was also conducted to validate the information collected through questionnaire and get additional information which was not covered in the questionnaire. Tools such as descriptive statistics and correlation analysis have been used for data analysis and to measure the vital relationship of each principle with the help of SPSS for WindowVersion20. The study pointed out the current situation of quality and quality management system and practices of its principles in Ethiopian Plastic Industries. The study has showed that employees have good quality awareness level; but, the participation of the employees in quality activities is low. The QMS practice of Ethiopian Plastic Industries indicated that organizations have prepared training programs for their employees; however, the trainings have no direct relevance to successfully deploy QMS as a result of the trained employees carry out activities affecting quality. The surveyed industries have less quality records and not properly filed for easy retrieval as a basic requirement for continuous improvement. Finally, based on the results of correlation analysis, a four-phased QMS implementation schema has been designed. It uses the deployment of QMS principles for the successful implementation and instrument for continuous process quality improvement of QMS in Ethiopian Plastic Industries.