The present study was conducted to evaluate and compare the effects of the Distal Jet and First Class appliances in distalizing maxillary first molars. The sample consisted of twenty female patients with a mean age of 14.6 years. The patients were divided randomly into two equal groups. In the first group Distal Jet appliances were used to distalize the maxillary first molars. On the other hand, First Class appliances were utilized for molar disalization in the second group. The disalization of the first molars were stopped when Class I molar relations were obtained. For all patients pre and post-distalization lateral cephalometric radiographs were taken. The results revealed that either appliance significantly distalized the maxillary first molars. However, the incisors were significantly tipped labially. Also, in both groups; no significant skeletal changes in the anteroposterior direction were found. The mandible showed significant clock-wise rotation. Regarding the difference between the two groups, the distalizing time of the First Class appliance was significantly shorter than that of the Distal Jet. However, the distal tipping of the maxillary first molars was significantly greater in the First Class group than in the Distal Jet group. The other parameters were not significantly different between the two groups. According to the results of the present study; the following could be concluded; both the Distal Jet and the First Class appliances were effective and reliable methods for maxillary first molar distalization. The First Class appliance distalized the maxillary molars in shorter time than the Distal Jet appliance but with greater distal tipping. Labial tipping of the incisors and clock-wise mandibular rotation occurred with both appliances. No significant skeletal changes in the anteroposterior direction found with either appliances.