The integration of Artificial Intelligence (AI) into language education has increasingly attracted scholarly and pedagogical attention. In TESOL contexts, where providing individualized and timely feedback remains a persistent challenge, AI-based tools offer potential solutions to enhance writing development. This study investigates the impact of AI-assisted feedback on the writing performance of intermediate English as a Foreign Language (EFL) learners. Over a six-week instructional period, one group of students received traditional teacher feedback, while another group received a combination of teacher and AI-generated feedback. Pre- and post-intervention writing tasks were analyzed using standardized assessment criteria. The findings indicate that students exposed to AI-supported feedback demonstrated greater improvement in grammatical accuracy, lexical diversity, and revision strategies. The results suggest that AI technologies can effectively complement teacher instruction and promote learner autonomy when integrated thoughtfully within TESOL pedagogy.