The purpose of the present study was to examine whether serum vitamin D status is associated with a change in gait speed in young adults. In this cross-sectional study, 60 young adults aged ≥ 19 years (36 female and 24 male participants) were recruited from the general population. Spatiotemporal parameters of gait were assessed by using a validated wireless inertial sensing device. The blood vitamin D status was classified as deficiency (<12.5 ng/ml), insufficiency (≥ 12.5 ng/ml to <20 ng/ml), and sufficiency (≥ 20 ng/ml). Linear increases in physical performance parameters such as grip strength, gait speed, stride length, and High-Density Lipoprotein Cholesterol (HDL-C) were found across the incremental categories of serum 25-hydroxyvitamin D (25(OH)D). A significant positive association was observed between serum 25(OH)D levels and HDL-C (r=0.759, P=0.001), grip strength (r=0.329, P=0.011), gait speed (r=0.873, P=0.001), stride length (r=0.690, P=0.001), and swing phase (r=0.322, P=0.013). A decline in gait speed was more likely to be associated with serum 25(OH)D deficiency (Odds Ratio: (OR), 13.1; 95% Confidence Interval (CI), 3.84-45.02; adjusted OR, 13.9; 95% CI, 3.61-53.7). To our knowledge, this cross-sectional study is the first to report that higher serum 25(OH)D levels are associated with gait ability and lipid parameters in young adults. Multiple regression analysis showed that vitamin D status is an independent predictive factor for a decline in gait speed.