The integration of artificial intelligence (AI) into language instruction has presented new opportunities, with ChatGPT emerging as a promising tool for interactive and personalized learning. This systematic review examines the effectiveness, advantages, and drawbacks of the ChatGPT in English language teaching (ELT). To achieve this objective, peer-reviewed studies published between 2023 and 2024 were sourced from the Web of Science database and focused on those that explored ChatGPT for language instruction. Using standardized criteria, data extraction covered the study design, participants, interventions, outcomes, and quality assessments. The findings indicate that the ChatGPT significantly improves language teaching by providing personalized feedback, fostering learner autonomy, enhancing student motivation and engagement, and facilitating specific language skills. Moreover, its ability to simulate real-life conversations makes it an effective tool to improve language fluency and comprehension. Nevertheless, challenges have been highlighted, such as overreliance on AI, academic dishonesty, skill deterioration, biases in AI-generated content, and the digital divide affecting access to AI technology. Integrating AI into existing educational frameworks and addressing the need for teacher training have also emerged as significant concerns. The implications are provided based on these findings.