Aim: Interleukin-17 (IL-17) is a proinflammatory cytokine that plays an important role in inflammation and tissue destruction in periodontal disease. This study aimed to assess the level of IL-17 in gingival crevicular fluid (GCF) of patients with chronic periodontitis (CP) and healthy controls. Materials and methods: This case-control study was performed on 30 patients with CP (53 males, 47 females, mean age of 37.2 ± 5.95 years) and 30 healthy controls (53 males, 47 females, mean age of 30.63 ± 5.22 years). The GCF was collected using paper points. A paper point was inserted into the pocket and remained there for 30 seconds. It was then placed in a sterile tube containing 300 µL of phosphate buffered saline and stored at-70° C. Level of IL-17 was measured using enzyme-linked immune sorbent assay (ELISA). The level of IL-17 was compared between the two groups using independent sample t-test at 0.05 level of significance. Results: The mean GCF level of IL-17 was 53.46 pg/L in CP patients and 38.1 pg/L in healthy controls. This difference was statistically significant (p = 0.025). Conclusion: The CP patients had significantly higher GCF level of IL-17 compared to healthy controls. Clinical significance: The finding of this study highlight the role of IL-17 in the pathogenesis of periodontal disease. Within the limitations of the present study, it may be suggested that measurement of GCF level of IL-17 can serve as a bioindicator of periodontal destruction and gingival inflammation. © 2018, Jaypee Brothers Medical Publishers (P) Ltd. All rights reserved.