This study investigated the impact of vitamin D status on the susceptibility and severity of viral pneumonia (VP) in children. A total of 236 children with VP, aged from 1 month to 14 years, and 271 gender and age matched healthy children to compare the serum 25(OH)D levels and vitamin D status. Vitamin D indices were compared between subgroups in VP cases. The median [interquartile range (IQR)] serum 25(OH)D level in these 507 children was 23.7 (IQR 17.5-30.6) ng/mL; 134 (26.4%) children were vitamin D sufficient [25(OH)D ≥30 ng/mL], whereas 373 (73.6%) were insufficient, which included insufficient [25(OH)D 20-30 ng/mL], deficient [25(OH)D 10-20 ng/mL], and severely deficient [25(OH)D ≤10 ng/mL]. The median (IQR) serum 25(OH)D level in the VP group was significantly lower than that in the control group [19.6 (12.3-26.4) ng/mL versus 26.6 (21.4-32.9) ng/mL] (P < 0.001). The proportions of vitamin D deficiency (32.2% versus 19.5%) and severe deficiency (19.1% versus 0.4%) in the VP group were significantly higher than those in the control group (P < 0.001). As vitamin D status decreased, the odds ratio (95% confidence interval) for VP showed an increasing trend [sufficiency (0.3; 0.2-0.5), insufficiency (0.9; 0.6-1.3), deficiency (2.0; 1.3-2.9), and severe deficiency (51.7; 7.2-372.2)]. The median (IQR) serum 25(OH)D level in the VP subgroup who accepted mechanical ventilation was significantly lower than that in the nonmechanical ventilation subgroup [12.9(6.5-22.5) ng/mL versus 20.8 (14.2-28.0) ng/mL] (P < 0.001). Poor vitamin D status might be related to the susceptibility and severity of VP in children. © Copyright 2017, Mary Ann Liebert, Inc. 2017.