Currently enthusiasm for mentoring of new teachers has re-emerged among teacher employing authorities in Australia and the United States. The literature on mentoring provides strong support for the importance of mentoring in retaining good teachers and in invigorating the teaching workforce; it also abounds in practical strategies and processes for developing and managing mentoring programs. This paper examines several contextual aspects affecting mentoring in the current educational landscape: the differentiated impact of teacher supply, appointment and retention; changing teacher entry and career pathways; an expanded knowledge base for teaching, accompanied by increased accountability; systemic preparation and reward of mentors; and improved communication technology. Based on the premise that all learners in all schools are entitled to high quality teachers, the paper explores the potential of mentoring as both promising and risky, and calls for research to monitor the impact of mentoring on both teacher retention and learning outcomes for all children.