The aims of the study were to examine whether self-reported physical health changes over the first 5 years after traumatic brain injury (TBI), and whether the trajectories of physical health over that time period could be predicted by demographic and injury-related variables. A longitudinal cohort study was conducted with 97 individuals with moderate-to-severe TBI who had been admitted to a Trauma Referral Centre in 2005/2007. Patients were followed up at 1, 2 and 5 years post-injury. Physical health-related quality of life (HRQL) (i.e., physical health) was measured by four subscales of the Medical Outcomes 36-Item Short Form Health Survey (SF-36): Physical Functioning, Role-Physical, Bodily Pain and General Health. Only the Physical Functioning domain showed statistically significant improvements across time. Women had lower scores on Role-Physical, Bodily Pain (more pain) and General Health. Unemployment prior to injury and having been in a "blue collar" physical job was associated with lower Physical Functioning and General Health, while greater TBI severity was associated with lower Physical Functioning, but better Role-Physical. Bodily Pain, Role-Physical and General Health remained fairly stable over time, despite the improvement in Physical Functioning. There were a number of significant injury-related and demographic predictors across the four trajectories of physical health. A better understanding of factors influencing these domains over the first 5 years after TBI and effective pain reducing rehabilitation strategies are needed.