Background: Vitamin D comes in two forms: Ergocalciferol (D2) and cholecalciferol (D3). Aim: The study's goal was to find out what moms know, do, and think about vitamin D deficiency in their kids. An online cross-sectional study was used for the research. Methods: The researcher utilized a self-administered online questionnaire to gather information about the characteristics, knowledge, attitudes, and reported practices of 800 Saudi Arabian moms regarding vitamin D deficiency. Results: According to the findings, the mean age was 31.2±4.76, and more than half of the participants 8% had a university education. When it came to household income, the majority 90.1% reported that they had enough money. Also noted, participants who attended training courses, employee mothers, total practice, and total Attitude all had a significant favorable effect on their children's knowledge, with a p-value of less than 0.01. Employee moms, training course attendees, total practice, and overall Attitude were all found to have a significant favorable effect on mothers' practice, with a p-value of less than 0.01**. Conclusion: More than half of the mothers who participated in the study had an inadequate level of understanding. Less than two-thirds of those surveyed noted the deficient practice. Two-thirds of the moms who participated in the study had a negative attitude toward vitamin D deficiency. Additionally, the study discovered a strong positive correlation between total knowledge, total attitude, and total practice-related Vitamin D deficiency.