A certification offered by the Scrum Alliance. A difficult-to-obtain certification that enables people to teach Certified Scrum Master® and Certified Scrum Product Owner® courses. CSTs must demonstrate a deep knowledge and understanding of Scrum concepts, practices, and principles. To apply to be a CST, a candidate must hold an active Certified Scrum Professional® designation from Scrum Alliance, have extensive hands-on experience implementing Scrum inside organizations as a ScrumMaster, product owner, or development team member, and have taught Scrum in a co-training partnership with a CST or independently in a non-certified context. Synonymous with CST. See also CSM, CSPO, CSP.