Abstract Background: The primary aim of this study was to evaluate the dentoalveolar, skeletal, pharyngeal airway, cervical posture,hyoid bone position, and soft palate effects of myobrace and twin block appliances. The second aim was compare the appliances in terms of ease of use by assessing the factors that may influence patient compliance. Methods: : The study included thirty-six Class II division 1 patients (19 females, 17 males; mean age, 12.14 ± 1.23) who had previously been treated in the Orthodontic clinic at Sivas Cumhuriyet University Faculty of Dentistry. The patients were divided into two groups: Group 1: myobrace (n=18), Group 2: twin block (n=18). The effects of the appliances on the skeletal, dentoalveolar, soft tissue, craniocervical, and other anotomic structures were assessed using 46 measurements, 22 linear and 24 angular, on pre and post-treatment cephalometric radiographs. AudaxCeph 5.0 software (Ljubljana, Slovenia) was used for the analysis. To analyze the changes after one year of treatment, a paired sample t-test and Wilcoxon signed-rank test were used. Intergroup comparison was performed by using the Student t-test and the Mann–Whitney U test. Results: In the myobrace and twin block groups, there was a significant increase in SNB 0 (p=0.004, p=0.001), IMPA 0 (p=0.005, p=0.001), and a significant drop in U1/SN 0 (p=0.021, p=0.005). The lengths of Cd-Gn (mm), Go-Pg (mm), and Cd-Go (mm) increased significantly in the twin block group (p=0.003, p=0.010, p=0.001), whereas there was no change in the myobrace group. Similarly, there was no significant difference in pharyngeal and soft palate measurements in the Myobrace group, but there was a statistically significant decrease in SP length and SP angle in the twin block group (p=0.001, p=0.006). Increases in SN/OPT 0 (p=0.032, p=0.001) and SN/CVT 0 (p=0.012, p=0.001) were statistically significant in both groups. Myobrace was more difficult to use while sleeping, whereas twin block caused more nausea. Conclusions: Both appliances can be used for mandibular advancement. The twin block appliance, on the other hand, was more effective and patient-friendly.