This chapter traces the evolution of technology integration in TESOL over the past five decades, from early Computer-Assisted Language Learning (CALL) to Technology-Enhanced Language Learning (TELL) and the current emergence of Artificial Intelligence in Education (AIED). It reviews key phases of CALL development and shows how multimedia resources, mobile learning, digital platforms, and online assessment practices laid the groundwork for GenAI adoption. Drawing on survey and interview data from TESOL educators working in diverse contexts, the chapter analyses patterns of technology adoption and demonstrates how prior experience with digital tools shapes educators’ readiness to engage with GenAI. It situates these findings within established frameworks, including the Technology Acceptance Model, diffusion of innovations, and core Second Language Acquisition theories related to input, output, and interaction. The chapter also examines how GenAI extends earlier technological affordances while introducing new pedagogical and ethical challenges. It concludes by highlighting persistent barriers, including access, infrastructure, and professional development, and by addressing concerns related to bias, privacy, academic integrity, and teacher autonomy. Responsible and critically-mediated integration is therefore framed as essential to ensuring that GenAI enhances, rather than undermines, TESOL practice.