Introduction: Orthodontic relapse is a physiological response of the supporting tissues to force application threatening the success of orthodontic therapy. The objective of this study was to evaluate the influence of local application of simvastatin on the magnitude of orthodontic relapse. Methods: Orthodontic tooth movement was induced in 10 white New Zealand rabbits. After 21 days of active tooth movement, orthodontic appliances were removed and the experimental teeth were allowed to relapse for further 21 days. During the relapse phase, one mandibular quadrant received local simvastatin administration while the corresponding mandibular quadrant received control vehicle solution on a weekly basis. Magnitudes of experimental tooth movement and post-orthodontic relapse were calculated. Results: The mean relapse magnitude was 1.31±0.53mm in the quadrant receiving control vehicle solution and 1.14±0.47mm in the quadrant receiving simvastatin administration. Neither the relapse magnitude nor the relapse percentage showed a significant difference between the two quadrants. Conclusion: Local simvastatin administration could not minimize post-orthodontic relapse magnitude to a significant level.