The relationships that clients form with their practitioners can influence treatment outcomes. Researchers have shown in numerous healthcare professions including psychology and physiotherapy that caring and collaborative relationships can lead to positive psychological and physical treatment outcomes, and poor relationships can lead to negative outcomes. Within sport psychology, there are fewer studies on clientpractitioner relationships in comparison to other domains of psychology or healthcare. Researchers and practitioners have often favoured the investigation and application of mental skills (e.g., goal setting, imagery, self-talk) over the exploration and development of client-practitioner relationships. In the specific context of sport injury rehabilitation, there exist few studies or commentaries on client-practitioner relationships as interventions that can aid athletes’ recoveries, transitions, and returns to sport. The aim of this thesis was to explore the relationships psychologists and physiotherapists have with injured athlete-clients and how these practitioners collaborate in sport injury rehabilitation.