ISO 9000 is a family of standards for quality management systems. ISO 9000 is maintained by ISO, the International Organization for Standardization and is administered by accreditation and certification bodies. Some of the requirements in ISO 9001 (which is one of the standards in the ISO 9000 family) include:-

• a set of procedures that cover all key processes in the business
• monitoring processes to ensure they are effective
• keeping adequate records
• checking output for defects, with appropriate and corrective action where necessary
• regularly reviewing individual processes and the quality system itself for effectiveness

A company or organization that has been independently audited and certified to be in conformance with ISO 9001 may publicly state that it is "ISO 9001 certified" or "ISO 9001 registered."ISO 9000 includes the following standards:

ISO 9000:2000, Quality management systems – Fundamentals and vocabulary. Covers the basics of what quality management systems are and also contains the core language of the ISO 9000 series of standards. A guidance document, not used for certification purposes. This has been revised in year 2005.

ISO 9001:2008 / ISO 9001:2015 Quality management systems – Requirements is intended for use in any organization which designs, develops, manufactures, installs and/or services any product or provides any form of service. It provides a number of requirements which an organization needs to fulfill if it is to achieve customer satisfaction through consistent products and services which meet customer expectations. It includes a requirement for the continual (i.e. planned) improvement of the Quality Management System, for which ISO 9004:2000 provides many hints. This is the only implementation for which third-party auditors may grant certification. It should be noted that certification is not described as any of the 'needs' of an organization as a driver for using ISO 9001 (see ISO 9001:2000 section 1 'Scope') but does recognize that it may be used for such a purpose (see ISO 9001:2000 section 0.1 'Introduction').

ISO 9004:2000 Quality management systems - Guidelines for performance improvements. covers continual improvement. This gives you advice on what you could do to enhance a mature system. This standard very specifically states that it is not intended as a guide to implementation.