Collaborative AI offers a timely and practical roadmap for educators navigating the challenges and opportunities of teaching in an AI-rich world. Grounded in the principles of ethical integration and human-centered pedagogy, this book introduces the concept of "Collaborative AI" - a framework that emphasizes the productive partnership between human educators and AI systems. Rather than replacing teachers, AI is positioned here as a tool to enhance language instruction, streamline assessment, and personalize learning while safeguarding professional autonomy and student agency. Written for TESOL professionals, applied linguists, teacher educators, and instructional designers, this book blends accessible explanations of AI technologies - generative AI, natural language processing, machine learning--with real world examples, pedagogical strategies, and policy guidance. Joshua M. Paiz covers key issues such as digital equity, data ethics, academic integrity, and professional development, offering concrete suggestions for classroom use and institutional planning. Across nine chapters, Collaborative AI guides readers through the history, potential, and pitfalls of AI in English language teaching, concluding with an optimistic yet critical call for educators to lead the way in shaping responsible and inclusive AI practices. This is a must-read resource for anyone seeking to integrate emerging technologies into language education while keeping pedagogy, ethics, and learner well-being at the center.