This chapter addresses the key international standards relating to quality management systems and projects. It warns that compliance with standards can become an end in itself, not the means to success. ISO 9001 compliance doesn’t guarantee a successful result, just consistent approaches. The ISO standards particularly relevant to project quality (9000, 9001, 9004, 19011 and 10006) provide a common vocabulary and good advice on systematic approaches to delivering quality, and the scope of these are covered briefly. Product quality standards (Kitemark, CE Mark) are described. Maturity assessment of project management performance is considered as a driver for performance improvement. The development and use of Standard Operating Procedures is a powerful way of both improving consistency and reducing errors, and the challenges and approaches to achieving this are discussed.