Background: The COVID-19 pandemic caused a global public health problem with high morbidity and mortality rates. In this study, we aimed to evaluate the 25-hydroxyvitamin D (25(OH)D) status of patients presenting to the Pediatrics Department of Gaziantep Maternity and Children's Hospital in the 1-year period after the onset of the COVID-19 pandemic according to ethnicity, age, and gender. Method: This cross-sectional study included the data of 7640 patients whose 25(OH)D levels were assessed at our hospital between March 2021 and March 2022. Vitamin D levels, age, gender, and the ethnic origin of the patients were retrospectively scanned and recorded from the laboratory results system. Based on the World Health Organization (WHO) classification of vitamin D levels, patients were divided into three groups: <10 ng/mL = vitamin D deficiency; 10–19 ng/mL = vitamin D insufficiency, and 20 ng/mL and over = normal vitamin D status. Results: The mean age of the 7640 patients who presented to the pediatrics department was 7.47 (±5.3) years. Of these patients, 48 % (3665) were male and 52 % (3975) were female. The mean vitamin D level of girls was 18.1 (±15.2) ng/mL, and of boys it was 20.2 (±15.4) ng/mL, with a statistically significant difference (p < 0.001). In total, 21.2 % (1650) of patients had deficient, 43.3 % (3310) of patients had insufficient, and 35.5 % (2710) of patients had normal 25(OH)D levels. Overall, 21.8 % of the patients (1667) were immigrants, and in this group the deficiency was found to be statistically significantly higher at 27.4 % (n = 456; p < 0.001). There was a low negative correlation between the age of the patients and their 25(OH)D levels (r=−0.35; p < 0.001). Conclusions: Vitamin D deficiency remains a serious public health problem. Since the most important production source is exposure to the sun, it must be kept in mind that vitamin D should be supported during lockdown pandemic processes.