OBJECTIVE:The association between effort-reward imbalance (ERI) and various health outcomes has been well documented over the past 20 years, but the mechanisms responsible for this association remain unclear. The present meta-analysis assessed the associations of ERI and overcommitment (OC) in the workplace with hypothalamic-pituitary-adrenal (HPA) axis measures. METHODS:Electronic databases were searched with the phrase "effort*reward*imbalance," which yielded 319 studies leading to 56 full-text studies being screened. Thirty-two studies within 14 articles met inclusion criteria and were meta-analyzed using mixed and random effects models. RESULTS:Greater ERI was associated with increased HPA axis activity (r = .09, p < .001, k = 14, N = 2541). The cortisol awakening response (r = .14, p < .001, k = 9, N = 584) and cortisol waking concentrations (r = .12, p = .01, k = 6, N = 493) were the only HPA measures associated with ERI. OC was also associated with greater HPA axis activity (r = .06, p < .01, k = 10, N = 1918). Cortisol (PM) (r = .13, p = .02, k = 3, N = 295) was the only HPA measure associated with OC. CONCLUSIONS:ERI and OC were similarly related with HPA responsivity. However, because OC moderated the relationship between ERI and HPA axis markers, the importance of OC should not be overlooked. Because OC is likely more malleable than ERI to intervention, this may be a promising avenue for future research.