Introduction: The biological markers measurement in the GCF and their relationship with clinical effect can be helpful for supervising and forecasting the orthodontic treatment effect. PGE2 is one of the initial biomarker for bone resorption, which can be used to supervise orthodontic tooth movement. Aim: This research aim to evaluate the association of leptin level on orthodontic tooth movement. Material and method: An observational prospective study was carried out on 40 participants attending Department of Orthodontics School of Dental Sciences In present study forty orthodontic patients were included. Concentration of leptin was assessed at baseline (T0), 1 hr after application of force (T1), 24 hours later (T2), 15 days after application of force (T3), and after 2 months of orthodontic force (T4). GCF was collected with help of strips of filter paper, from sulcus of gingiva on right maxillary canine’s distal aspect. Distalized tooth movement was evaluated by measuring the difference on dental casts, at baseline and 2 month following force application. Obtained data was statistically evaluated.