Obtaining a doctoral degree requires acquisition of different types of skills and knowledge. The aim of this article is to explore multidisciplinary peer-mentoring groups (PMGs) facilitated by senior academics as a knowledge sharing practice in doctoral education. Drawing from interviews with participants of PMGs at a Finnish university, we found that the participants perceived that cultures and practices of doctoral education in departments and faculties, as well as limited support from supervisors might hinder knowledge sharing. They highlighted that a flat hierarchy and confidential atmosphere supported by the multidisciplinary group composition promoted knowledge sharing and emotional support. Based on these results, we argue that PMGs are a useful resource for facilitating knowledge sharing amongst doctoral researchers and thus have a capacity to benefit the individual as well as the organisation as a whole.