This study aimed to investigate the presence of specific immunoglobulin G antibodies against Toxoplasma gondii infection among diabetic and nondiabetic participants in Najran, Saudi Arabia. As much as 5 mL of blood was collected from each participant during the period of 6 months (from November 2020 to April 2021). T. gondii immunoglobulin G antibodies were analyzed by enzyme-linked immunosorbent assay test kits. The cut-off values for T. gondii immunoglobulin G levels to be considered positive were ≥8 IU/mL. A total of 200 blood samples were obtained from the diabetic; and 100 samples from the nondiabetic participants. Among the diabetic patients, 67% were seronegative, 2% were equivocal, and (31%) were seropositive. However, among the nondiabetic participants, 78% were seronegative, 2% were equivocal, and 20% were seropositive. The seroprevalence of the T. gondii immunoglobulin G antibodies was higher in the diabetic patients compared to the control group; and the diabetic patients above 21 years of age had twice the higher risk of immunoglobulin G seropositivity compared to their younger counterparts. Diabetes, by lowering the immune response, may act as a confounding factor of toxoplasmosis infection and vice versa. The association between the two and the causes should be investigated more in detail.