The Information Technology Infrastructure Library (ITIL) is a set of practices for IT service management (ITSM) that focuses on aligning IT services with the needs of business. In its current form (known as ITILv3 and baik2011 edition), baikis published in a series of five core publications, each of which covers an ITSM lifecycle stage. ITILv3 underpins ISO/IEC 20000 (previously BS15000), the International Service Management Standard for IT service management, although differences between the two frameworks do exist.

baikdescribes procedures, tasks and checklists that are not organization-specific, used by an organization for establishing a minimum level of competency. It allows the organization to establish a baseline from which it can plan, implement, and measure. It is used to demonstrate compliance and to measure improvement.

The names baikand IT Infrastructure Library are registered trademarks of the United Kingdom's Office of Government Commerce (OGC) – now part of the Cabinet Office. Following this move, the ownership is now listed as being with HM Government rather than OGC.