This study investigates Thai secondary school English teachers’ perceptions of ChatGPT in language education, offering context-sensitive insights from an underexplored Southeast Asian EFL context. Using a mixed-methods approach, data were collected from 31 teachers through surveys and five semi-structured interviews. Most participants reported moderate to high levels of familiarity with ChatGPT and recognized its value for lesson planning and grammar support. However, they also expressed concerns about plagiarism, student overreliance, and the potential weakening of critical thinking skills. Despite these reservations, teachers showed cautious openness to integrating ChatGPT into classroom instruction, provided that structured professional development, clear ethical guidelines, and sustained institutional support are available. Participants emphasized the importance of strengthening artificial intelligence (AI) literacy among students and called for clearer policy direction at both institutional and national levels. These perspectives were shaped by Thailand’s exam-oriented education system and persistent digital inequality. Overall, the findings indicate that effective AI adoption in Thai EFL classrooms requires not only pedagogical readiness but also policy coherence and infrastructural equity.