This technical manual describes the purpose and intended uses of the TOEFL iBT test, its target test-taker population, and relevant language use domains. The test design and scoring procedures are presented first, followed by a research agenda intended to support the interpretation and use of test scores. Given the updates to the test starting January 2026, this technical manual is intended to serve as an overview and rationale for the test design as well as a reference point for informing investigations of validity evidence to support the intended test uses over time. Designed as a living document, this manual will be updated as the test's design, administration, scoring, and evidence of measurement quality (including reliability, validity, and fairness) evolve, along with its intended uses.