In this paper, boundary management illuminates understanding of the doctoral supervisory relationship. Boundary management is presented as a theoretical vehicle that helps to define and explain roles that supervisors employ at different junctures along the doctoral journey and how transitions between these are negotiated. The paper draws on the work of Ashforth, Kreiner, and Fugate who suggest that the concept of boundaries "in numerous disciplines" refers to "physical, temporal, emotional, cognitive and/or relational limits" that define how, for example, roles are distinguished from one another. Adapting this work to the doctoral supervisory relationship, temporal and cognitive dimensions are defined as "primary" boundaries and physical emotional and relational aspects as "secondary" ones. Managing primary boundaries is integral to supervising the entire doctoral journey. However, engaging with secondary dimensions is also critical to shape how supervisors construct and negotiate the key elements of time and cognitive development throughout that journey.