Aim of study: The purpose of this study was to evaluate the effects of Modified Tandem Appliance (MTA) in management of Class III cases due to maxillary retrusion. Material and method: Ten female patients with skeletal Class III malocclusion due to maxillary retrusion were selected for this study. The mean age of the patients was 8 years 3 months. All patients were treated with the MTA for one year. Cephalometric radiographs and plaster study models were made at two stages; before and after one year of treatment with the MTA. The cephalometric radiographs and the study models were analyzed and the collected data were subjected to statistical analysis. T-test was done to determine the significance difference between the pretreatment and posttreatment measurements. Results: The use of MTA significantly enhanced the forward growth of the maxilla without any noticeable effects on the mandible. The anterior and posterior facial height were significantly increased. There were a significant increase in the proclination of the upper incisors and retroclination of the lower incisors. In addition, there were significant increase in the upper and lower intermolar widths and also, in the upper intercanine width. Conclusion: The MTA was effective in the treatment of skeletal Class III malocclusions due to maxillary retrusion. It had a combination of skeletal and dental effects.