Quality assurance has been a prime concern for teachers and institutions involved in English language teaching and learning for many years, although how quality has been conceptualized and determined has certainly changed. For example, as a profession, we have considered different measures of quality, such as selecting the most effective methodology, teaching to standards, and including online technologies in course design and development. The processes involved in assuring quality, the stakeholders, and the constructs related to assuring quality continue to change as the profession matures and develops. While some of the ways in which we conceptualize quality are a result of the research and the dissemination of new knowledge within the profession and are now based on learning outcomes, quality assurance has also been conceptualized in terms of how teachers and institutions respond to external influences, such as the rapid expansion of English as a lingua franca and recent advances in the use of online technologies, as well as political change and economic growth and development in specific regions around the world. It stands to reason that these changes, both local and global, must be taken into consideration when assuring quality. In this chapter, we explore the concept of quality within the profession of TESOL from a historical perspective by examining how quality has been conceptualized in our profession in order to be responsive to the challenges that face us in the future.