Background: Periodontitis and type 2 diabetes mellitus are both considered as a chronic disease that affect many people and have an interrelationship in their pathogenesis. Objective: The aim is to evaluate the salivary levels of interleukin-17 (IL-17) and galectin-3 in patients with periodontitis and type-2 diabetes mellitus. Materials and Methods: The samples were gathered from 13 healthy (control group) and 75 patients split into 3 groups, 25 patients with type 2 diabetes mellitus and healthy periodontium (T2DM group), 25 patients with generalized periodontitis (P group), and 25 patients with generalized periodontitis and type 2 diabetes mellitus (P-T2DM group). Clinical periodontal parameters were documented. The concentration of IL-17 and galectin-3 in salivary samples was estimated using enzyme-linked immunosorbent assay. Result: The concentration of IL-17 in the T2DM group (388.612 ± 120.111 pg/mL), the P group (443.887 ± 69.188 pg/mL), and the P-T2DM group (532.769 ± 137.673 pg/mL) showed higher values than the control group (292.079 ± 62.356 pg/mL) with a significant difference at (P < 0.05). Also, the P-T2DM group showed higher values than the P group and the T2DM group with a significant difference (P < 0.05). The concentration of galectin-3 in the T2DM group (2.409 ± 0.147 ng/mL), the P group (2.699 ± 0.386 ng/mL), and the P-T2DM group (2.568 ± 0.285 ng/mL) showed higher values than the control group (1.888 ± 0.356 ng/mL) with a significant difference (P < 0.05). The P group showed a higher value than the T2DM group with a significant difference (P < 0.05). Conclusion: Salivary IL-17 and galectin-3 levels might be used as a biomarker for periodontitis.