Thesis (PhD(Psychology))--University of South Australia, 2017. Includes bibliographical references (pages 132-150) While the field of work and organisational psychology has demonstrated that psychosocial factors influence worker health and wellbeing there is an ongoing need to build upon the evidence base clarifying how psychosocial factors impact worker health and organisational productivity outcomes. In particular, to identify the origins of psychosocial factors at work by extending upon several already established models for work stress. Psychosocial safety climate (PSC) is presented in this thesis as a preeminent indicator for psychosocial factors at work and is scrutinised for it capacity to predict worker health and organisational productivity outcomes. The results from the studies in this thesis provide numerous theoretical contributions. First, is that psychosocial factors beyond psychological health, impact upon employee physical health outcomes. The longitudinal study design utilised a lagged model that included interview results for 1,095 Australian workers interviewed on two occasions 12 months apart. Outcomes established that emotional exhaustion, preceded by PSC, mediates the relationship between job demands (work pressure, bullying, and harassment) and MSDs, and has a significant impact on workers’ compensation claims for physical injuries. Further, results identified a pathway where by PSC was related to compensation claims via harassment, bullying, and violence. An integrated model including both psychosocial and physical pathways for assessing worker health and wellbeing is presented.