An Accredited Certification Body is an organisation accredited by an authorising body such as UKAS (the UK Accreditation Service) to undertake third party assessment of management systems such as ISO9001, ISO14001 and ISO27001, and to award and withdraw Certificates of registration to these standards.

This should not be confused with an accreditation body, which is an organization (usually a national one) that grants the actual authority to issue 'certificates' (to certify) to the certification body.

There are a growing number of Certification Bodies.