The prevalence of vitamin D deficiency, prediabetes, and diabetes is increasing worldwide, including in Saudi Arabia. Vitamin D deficiency is a risk factor for the development of diabetes and dyslipidemia [12]. Our results showed that 30.9% of the participants had vitamin D deficiency, which is similar to a previous study by Alsuwadia et al [15], which found vitamin D deficiency in 29% of the subjects. In addition, vitamin D deficiency was more common in women (64%) than in men (36%) among all participants. AlFaris et al [16] noted that vitamin D deficiency is a common health problem in Middle Eastern countries, with women being more commonly affected. However, women's traditional dress in Saudi Arabia, diet, and lifestyle could be a predisposing factor for vitamin D efficiency [17]. Our results showed a statistically significant decrease in the main vitamin D levels (P = 0.0004) in prediabetics (24.8 ± 10.5) compared with nondiabetics (30.2 ± 12.5 ng/ml). However, several studies have investigated vitamin D levels in diabetic and prediabetic patients. Gao et al [18] found a significant relationship between low vitamin D levels and an increased risk of prediabetes in their study.