This repeated-measures laboratory study characterized the relative impacts of vertical-axial dominant and multi-axial Whole-Body Vibration (WBV) exposures on postural stability. Eleven healthy participants were exposed to field-measured vibration profiles collected from on-road commercial (vertical-dominant WBV) and off-road mining vehicles (multi-axial WBV) for four hours on two different days. Before and after the exposure, postural stability was evaluated while participants performed sit-to-stand tasks followed by static standing tasks. Overall, the study results indicate that off-road, multi-axial WBV may compromise postural stability more so than on-road, vertical-dominant WBV. These findings may suggest that off-road vehicle operators are at a greater risk of fall-related injuries. Therefore, there is a critical need to develop more effective vibration control measures among off-road vehicle operators.