An enduring theme of social work literature and education has been the need for workers to recognise and challenge oppressive structures and develop competence in working with diverse client groups. This paper reports the findings of a qualitative research project where student and field educator supervision sessions were recorded, with the view to examining how oppression and diversity were addressed in these sessions. The authors have used the term 'difference' to describe the breach between the student and client experiences. Examples of anti-discriminatory practice were identified in the recordings, however on occasions supervisors had difficulty in assisting students to acknowledge diversity and oppression in supervision. Four factors that related to addressing diversity emerged from the supervision material. These were: the struggle to unmask subtle themes of oppression; the use of questioning to raise student awareness and development of self-knowledge; using student biography to facilitate learning on 'difference'; and field educator use of self-disclosure during discussions on diversity. Successful approaches to anti-oppressive practice and responding to diversity are outlined.