This study draws on the effort-reward imbalance (ERI) model of job stress to predict mental and physical health in academic employees working in United Kingdom universities. It examines the main and interactive effects of extrinsic efforts over time as well as the independent contributions of the three reward systems of the model (i.e., promotion, esteem, and security rewards). The main and interactive effects of intrinsic effort (known as overcommitment) in predicting health status are also examined. A sample of 458 academic employees completed ERI scales at baseline and the health measures 14 months later. Higher extrinsic effort, lower esteem and security rewards, and an imbalance between efforts and esteem rewards assessed at Time 1 were found to predict mental health status on follow up. Physical health symptoms were predicted by higher extrinsic effort and lower security rewards. Overcommitment was an independent risk factor for both mental and physical health. No further contribution was made to the variance in either outcome by the other effort-reward ratios independently or by their interactions with overcommitment. Interventions are suggested that have potential to reduce extrinsic and intrinsic efforts and increase rewards in the university sector. (PsycINFO Database Record (c) 2019 APA, all rights reserved)