Introduction Social capital is defined as resources embedded in social relationships. Social capital in the workplace may include social support, interpersonal trust, respect, and reciprocity; and may occur at both the worker and workplace level. The objective of this study was to determine if social capital in the workplace is associated with work-related injury or disability.

Methods A systematic review of the epidemiologic literature was conducted. Studies were identified from 1990 to 2008 relevant to social capital in the workplace and work-related injury or disability. Identified studies were critically appraised for methodological quality by two qualified independent reviewers. Findings represent a best evidence synthesis of the literature.

Results Sixty-six studies were scientifically reviewed. Forty-two were excluded due to poor methodological quality. The remaining 24 consisted of 14 studies examining the association between social capital in the workplace and work-related injury, eight focused on disability, and two studied both injury and disability. Only two studies included workplace-level social capital, the remaining focused on individual-level worker social capital. Limitations of the literature include unclear social capital, injury and disability definitions, limited study populations, and weak study designs.

Conclusions Limitations preclude stating consistent conclusions. The evidence suggests an association between individual worker social capital and work disability. Group-level social capital may be important in the development of work-related injury and disability. We summarised the literature, highlighted its strengths and weaknesses, and provided suggestions for future work.