This chapter examines the principles and the framework for quality management systems (QMSs) and quality assurance, as pertinent to on-treatment imaging for geometric verification. The system is the organisational structure, procedures, processes, and resources needed to implement quality management. There are seven key quality management principles involved, which are: customer focus; leadership; engagement of people; process approach; improvement; evidence-based decision making; and relationship management. The health care sector has various requirements for needing quality management and/or an accredited quality management system in place. The chapter provides the framework principles for good, secure, and accurate on-treatment verification imaging for guiding radiotherapy. It describes the benefit of regular audit, review, and potential change comes into its best work from the implementation of the QMS. The use of a QMS is recommended under a host of professional guidance documents within the UK and abroad.