To examine differences in the return to work (RTW) process for workers' compensation claimants with psychological injuries compared to those with musculoskeletal (MSK) injuries. We collected data from 869 workers' compensation claimants in Victoria, Australia, at three time points over a 12-month period (21% with psychological injury claims). RTW was assessed through self-report. Potential mediators were identified at the personal, health-care provider, workplace and system levels. The relationships between injury type, mediating factors and RTW were assessed using path analysis, with adjustment for confounders through inverse probability weighting. We observed better RTW outcomes for claimants with MSK injuries (compared to those with psychological injuries) at T1 and T2, but not at T3. We also observed differences between psychological injuries and MSK injuries and all but two of the mediating factors examined. These differences, in particular related to supervisor response to injury, consultative RTW planning and offers of accommodation, as well as differences in mental health symptoms, explained approximately two-thirds of differences in RTW between injury types at T1. Differences in RTW at T2 were explained by mediating factors, and differences in RTW at T1. Claimants with work-related psychological injuries experience a variety of challenges in RTW compared to those with MSK injuries. While treating and preventing further exacerbation of psychological symptoms should remain an important part of the rehabilitation process, other modifiable factors, in particular supervisor response to injury and consultative RTW planning and modified duties, should be prioritised to reduce inequalities in RTW across injury types.