Introduction: While there are a growing number of studies on the effects of medications on orthodontic tooth movement (OTM), only few studies have investigated the role of corticosteroids, despite their widespread use. The aim of the current study was to evaluate the effects of triamcinolone acetonide injection on OTM in a rabbit model. Study design: Sixteen one-month old rabbits were randomly divided into two groups: Eight rabbits had triamcinolone acetonide (1mg/kg/day) administered IM daily for 21 days (test group) while the remaining eight rabbits received no drug (control group). The rabbits in both groups had a tube bonded to the upper central incisors and a stainless steel helical spring was inserted in tube slot to apply 50 cN distal force. After 3 weeks, the rabbits were sacrificed and the distance between mesial corners of incisors was measured. The incisors are associated tissue was processed for histology and the apical and cervical area of the roots evaluated. An observer who was blind to the study groups evaluated the specimens. Results: All appliance-treated incisors in test and control groups showed evidence of tooth movement. The distance between the incisors was significantly greater in the triamcinolone acetonide treated group compared to the control group (P<0.001). Histological examination revealed an increased number of resorption lacunae and decreased number of cuboidal osteoblastic cells around the apical and cervical area of the Incisor roots in the test compared to the control group (P<0.01). Conclusion: Treatment with triamcinolone acetonide is associated with increased tooth movement in rabbits via increased resorptive activity in the alveolar bone.