Objective: The present study was conducted to evaluate posterior transverse changes of the maxillary dental arch in class II malocclusion accompanying maxillary molars distalization. Materials & methods:Twelve subjects with a mean age of 19.4 years, moderate skeletal class II malocclusion, dental class II molar relationship, and full permanent dentition participated in this study. Dental Cone Beam Computed Tomography scans (CBCT) were done before and immediately after distalization. Maxillary posterior segment was prepared for molar distalization by leveling and alignment till reaching stiff stainless steel arch wire. A miniscrew was inserted mesial to the maxillary permanent first molar and immediately loaded; and open coil spring was placed between maxillary second premolar and first permanent molar. Results:The maxillary second premolar moved buccally significantly by a mean of 2.01 mm; while the maxillary first and second molars showed highly significant buccal movement following distalization by means of 1.43 mm and 0.95 mm respectively. Conclusion:From the results obtained from this study, it could be concluded that using open coil spring and miniscrew as indirect anchor age during maxillary molars distalization; produces buccal expansion of maxillary dental arch.