Mentoring is an established method of support for principals as they commence their role as school leaders. However, there is limited research on the influence of mentoring on the development of leadership practices of newly appointed post-primary school principals in Ireland. As the role of a principal has evolved from a manager to a leader of learning, the role of mentoring has also evolved. The purpose of this general qualitative study is to explore the experiences and perceptions of newly appointed principals (NAPs) in relation to the effectiveness of a formal mentoring programme. This study addresses the following overarching research question: how can mentoring be used, if at all, to develop NAPs as leaders of learning? This inquiry led to the development of the following embedded questions linked to the overall research question: (1) What are NAPs’ perspectives of mentoring following a formal mentoring programme? (2) How has participants’ professional practice been influenced by their mentoring experience? The study considers the constructs of leadership for learning (LfL) and mentoring identifying key dimensions for each concept. Social cognitive learning theory is used as a theoretical bridge between these two concepts to explore NAPs’ learning experiences. Based on ten individual interviews and a focus group consisting of four participants, this study suggests that mentoring can support the development of NAPs’ LfL practices. This is achieved through four significant findings from this study: (1) the establishment of supportive relationships, (2) mentoring conversations that share learning experiences, (3) linking emotional awareness to leadership and (4) commitment on the part of the mentee to the mentoring process. In addition, this study sheds light on the importance of matching the mentor with the mentee, the philosophy of learning behind LfL and mentoring and mentoring as a form of social learning. The findings have implications for current and future mentoring programmes that aim to support NAPs as leaders of learning.