ISO/IEC 20000 is the first international standard for IT Service Management System. It was developed in 2005, by ISO/IEC JTC1 SC7 and revised in 2011. It is based on and intended to supersede the earlier BS 15000 that was developed by BSI Group.

Formally: ISO/IEC 20000-1 ('part 1') "promotes the adoption of an integrated process approach to effectively deliver managed services to meet the business and customer requirements". It comprises ten sections:

• Scope
• Terms & Definitions
• Planning and Implementing Service Management
• Requirements for a Management System
• Planning & Implementing New or Changed Services
• Service Delivery Processes
• Relationship Processes
• Control Processes
• Resolution Processes
• Release Process.

ISO/IEC 20000-2 ('part 2') is a 'code of practice', and describes the best practices for service management within the scope of ISO/IEC 20000-1. It comprises the same sections as 'part 1' but excludes the 'Requirements for a Management system' as no requirements are imposed by 'part 2'.

ISO/IEC 20000, like its BS 15000 predecessor, was originally developed to reflect best practice guidance contained within the ITIL (Information Technology Infrastructure Library) framework, although it equally supports other IT Service Management frameworks and approaches including Microsoft Operations Framework and components of ISACA's COBIT framework.