Introduction: This study was carried out to investigate the effect of bone anchored maxillary protraction (BAMP) on maxillarymandibular divergency during the treatment of growing patients with Class III malocclusion Methods: The sample of this study consisted of ten subjects (5 males and 5 females), (9-12 years old). Each treated patient had four miniplates inserted between the lower left and right lateral incisor and canine and on the left and right infrazygomatic crest of the maxillary buttress. Class III elastics were applied between the miniplates on each side for twenty four hours a day. Lateral cephalograms of each patient were evaluated at the beginning of treatment (T1), and at the end of active treatment (T2). The effect of treatment was compared to the effect of growth changes in a matched untreated control group of the same malocclusion. Results: the Pal-SN angle decreased -1.30º, the MP-SN angle decreased -0.60º, the Go angle decreased -2.10º, and the MP-PaL angle increased 1.20º. Conclusions: the BAMP approach induced a more counterclockwise rotation of the palatal plane than the mandibular plane that resulted in increase of Maxillomandibular divergency, but it was insignificant compared to the control group.