<![CDATA[This study aims to investigate undergraduate EFL students’ writing behaviors and ethical considerations in using Generative Artificial Intelligence (GenAI) during undergraduate thesis writing. The study focuses on how students use GenAI as an assistive tool in planning, drafting, and revising their theses, as well as how they maintain academic integrity in processing AI-generated outputs. This research employed a qualitative multiple case study design involving three undergraduate students at STIT Misbahudin Ahmad Blitar, a pesantren-based Islamic higher education institution in East Java, Indonesia. Data were collected through semi-structured interviews, observation, and document analysis, and were analyzed using the interactive model of Miles, Huberman, and Saldaña, consisting of data condensation, data display, conclusion drawing, and verification. The findings show that students used GenAI to explore topics, refine research titles, identify research gaps, formulate research questions, transform ideas into academic text, improve sentence clarity, correct grammar, and revise paragraph organization. However, they did not use GenAI passively. Students verified information, checked citations, paraphrased AI-generated text, compared suggestions with supervisor feedback, and adjusted outputs based on their research context. Ethical awareness also shaped their AI use, as students viewed GenAI as a supportive tool rather than a replacement for their own academic work. The study implies that GenAI can support thesis writing when guided by critical awareness, academic responsibility, and Islamic values. Therefore, institutions and supervisors should provide clear guidelines for ethical and responsible GenAI-assisted academic writing.]]>
