Background: The aim of this study was to investigate the effect on physical performance of combining whole-body vibration exercise (WBV) with parathyroid hormone 1-34 (teriparatide) compared to teriparatide alone. Methods: A secondary analysis from a RCT where postmenopausal women with severe osteoporosis were randomised to WBV plus teriparatide (intervention) or teriparatide alone (control). WBV was applied three times/week (6x1min WBV:1 min rest, (peak acceleration 3.6 g)) for twelve months. Both groups received teriparatide 20 μg s.c./day. The primary endpoint (bone mineral density) is reported elsewhere. Physical performance measures (Short Physical Performance Battery (SPPB), Timed-Up-and-Go (TUG), leg extension power, and grip strength) were obtained at baseline, three-, six-, and twelve months, lean mass at baseline and twelve months. Data were analysed with mixed linear regression model or robust cluster regression in an intention to treat analysis. Results: Thirty-five women aged (mean ± SD) 69 ± 7) years were recruited of which thirty-two (91%) completed the twelve months follow-up (WBV + teriparatide = 15, teriparatide = 17). SPPB score (mean ± SD) improved significantly at three months in the WBV + teriparatide group from 9.13 ± 2.03 to 10.35 ± 1.69 (p = 0.014) with a statistical trend towards a between-group change in favor of the WBV + teriparatide group (0.86 [95%CI(- 0.05,1.77), p = 0.065]). Both groups improved in leg extension power during the study period whereas no changes were seen in TUG, grip strength, or lean mass in either group. No statistical significant between-group differences were observed. Conclusion: WBV may improve some short-term aspects of physical performance in severely osteoporotic postmenopausal women who are receiving teriparatide treatment. Trial Registration: ClinicalTrials.gov, ID:NCT02563353