The present study examined whether job resources (job control, social support, and distributive justice) moderate the associations of high job demands induced by physical and mental workload with musculoskeletal symptoms among geriatric nurses. The data were drawn in Finland from 975 female nurses working in 152 geriatric units who responded to a survey questionnaire. Information on the objective workload in terms of resident characteristics and structural factors was also collected at the unit level. After adjusting for the objective workload, multilevel logistic regression analyses showed that self-reported physical workload was associated with higher risk of musculoskeletal symptoms (OR = 1.93, 95 % CI [1.38, 2.72]) among nurses with low social support. In addition, mental workload was associated with higher risk of musculoskeletal symptoms (OR = 1.72, 95% CI [1.12, 2.62]) for those with low distributive justice. The results suggest that social support and fair reward systems may help to buffer against the detrimental effects of heavy job demands on nurses' musculoskeletal symptoms.