During orthodontic treatment, mechanical forces may change the components of gingival crevicular fluid (GCF), which reflects the cellular response in the periodontium. The objective of this study was to investigate the expressions of receptor activator of nuclear factor-kappa beta ligand (RANKL) and interleukin- 17A (IL-17A) in GCF in subjects with or without orthodontic appliances, the correlation between them, their gender predominance, and their relationship with treatment time. GCF was collected from 72 young people to detect the expressions of RANKL and IL-17A. Cytokine analysis was done with the help of enzyme-linked immunosorbent assay. Results showed that the expressions of RANKL and IL-17A were higher in the treatment group than the nontreatment group (P .05) and higher in males than in females (P .05). Their increments were well correlated with each other (r = 0.788, P = .01) but were not time dependent. The authors concluded that these proteins increased in the treatment group and more in the young male orthodontic patients than in the female patients. The proteins were well correlated with each other.