Aim: To determine the effect of alfacalcidol on muscle strength and functional mobility in Indonesian older women whose handgrip strength was low. Methods: A randomized, double-blind controlled trial was carried out among 95 older women whose handgrip strength was ≤22 kg. Participants were randomized into two groups: 47 participants received alfacalcidol 0.5 μg/day and 48 participants received a placebo. Each participant in both groups was given calcium 500 mg/day. Handgrip strength as well as the Timed-Up and Go test were measured before and after 90 days of intervention. Per protocol analysis after intervention between two groups was carried out. Results: There was a significant improvement of handgrip strength in the group that received alfacalcidol compared with the placebo group (15.50 vs 13.75; P = 0.003). The median time for the Timed-Up and Go test in the alfacalcidol group also improved significantly compared with the placebo group (9.01 vs 10.07, P = 0.028). Conclusions: Alfacalcidol with daily doses of 0.5 μg significantly improved muscle strength and functional mobility in Indonesian older women. Geriatr Gerontol Int 2018; 18: 434–440.