This article will explore the importance of sound relationship-based practice in the supervision and assessment of social work students in practice learning. It will consider the origins of relationship-based practice and explore and analyse the literature and most notable theorists in this area. It will go on to explore the links between attachment theory and relationship-based practice in order to demonstrate its pivotal importance to social work practice. It will draw parallels between good relationship-based practice in the supervision of social work students and the formation of successful and meaningful working relationships between the students and the people they support on placement, giving attention to the theoretical concept of parallel process. It will provide practice examples from student supervision sessions to model how sound relationship-based practice compliments the assessment process with students, and leads to good partnership working and shared goals on placement. By providing practice examples it will demonstrate that good relationship-based practice between student and supervisor can lead to successful outcomes for students on placement which, in turn, can lead to successful outcomes for the people the students go on to support. It will argue that good relationship practice is the basis for all good social work practice and its foundations should be laid early within the practice teaching relationship between supervisor and student. Keywords: relationship-based practice; social work students; practice teaching; supervision; assessment