This paper provides insights into thesis supervisors' perceptions of the supervisory relationship and process in English-medium international master's degree programmes (IMDPs). It contributes to the field of supervisory pedagogy in a master's level education by examining how supervisors perceive their supervisory practices and what they consider to be the most important features for successful supervision. Twenty semi-structured interviews were conducted with thesis supervisors employed in five different Finnish universities. Qualitative content analysis was conducted. The results revealed that most of the interviewees perceive supervision as an asymmetric relationship in the context of a teaching model similar to Dysthe's (2002). Trust, topic selection, supervisors' support and the initial stage of supervision were regarded as the most important features during supervision. The article concludes with the recommendation that supervisors should have more opportunities to reflect on their supervisory practices.