PurposeTo determine fasting plasma glucose and serum 25-hydroxyvitamin D (s-25(OH)D) levels and associations between abnormal fasting plasma glucose levels and inadequate s-25(OH)D levels in individuals of Middle Eastern and Swedish descent.MethodsObservational study with individuals without a diabetes diagnosis, 54.5% of Swedish descent and 45.5% of Middle Eastern descent. In total, 830 participants from two primary healthcare centres in Flemingsberg and Jakobsberg, which are southern and northern suburbs, respectively, of Stockholm, Sweden were included in the study.ResultsPrevalence of inadequate s-25(OH)D levels (at or below 50 nmol/L) was 67.2% among those of Middle Eastern descent and 20.5% among those of Swedish descent (P< 0.001). S-25(OH)D levels correlated weakly positively with fasting plasma glucose levels (ρ = 0.20,P= 0.002) in individuals of Middle Eastern descent. Being of Middle Eastern descent (OR 6.7, 95% CI 4.3–10.4) and having abnormal fasting plasma glucose (OR 1.8, 95% CI 1.2–2.9) were independent predictors of having inadequate s-25(OH)D levels.ConclusionsHealthcare in Sweden should consider testing fasting plasma glucose and s-25(OH)D levels, particularly in individuals of Middle Eastern descent. The unclear relationship between vitamin D and glucose levels warrants investigation.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40200-023-01226-0.