In the last decade, research on the use of artificial intelligence technologies in education has steadily grown. Many studies have demonstrated the potential of these technologies to improve school administration processes, enhance students' learning experiences, simplify teachers' daily tasks, and broaden opportunities for lifelong learning. However, the enthusiasm surrounding these possibilities may overshadow the ethical challenges posed by these systems. This systematic literature review is designed to explore the ethical dimensions surrounding the utilisation of these technologies within the defined timeframe (2011-2022) in the field of education. It undertakes a thorough analysis of various applications and objectives, with a particular focus on pinpointing any inherent shortcomings within the existing body of literature. The paper discusses how cultural differences, inclusion, and emotions have been addressed in this context. Finally, it explores the capacity building efforts that have been put in place, their main targets, as well as guidelines and frameworks available for the ethical use of these systems. This review sheds light on the research's blind spots and provides insights to help rethink education ethics in the age of AI. Additionally, the paper explores implications for teacher training, as educators play a critical role in ensuring the ethical use of AI in education. This review aims to stimulate ethical debates around artificial intelligence that recognise it as a non-neutral tool, and to view it as an opportunity to strengthen the debates on the ethics of education itself.