Objective: The purpose of this research was to evaluate the effect of the incisal capped Twin Block on the proclination of the lower incisors in the treatment of skeletal class II malocclusion. Materials and Methods: Ten patients (age ranged from 9 to 14 y) with skeletal class II due to mandibular retrusion were selected and treated with the incisal capped Twin Block appliance. Overjet was more than 4 mm. Lateral cephalometric radiographs, photographs, and study casts were obtained before and after treatment. The collected data were analyzed using (SPSS) program for Windows (Standard version 26). The treatment duration was about 8-12 months. Results: Incisal capped TB appliance had Dento-skeletal and soft tissue effects including non-significant effect on the maxillary growth, significant advancement of the mandible, increase in the posterior and total anterior facial height, decrease in the overjet and overbite, retroclination of the upper incisors, significant proclination of the lower incisors and improvement of the soft tissue profile. Conclusions: The incisal capped Twin Block appliance was effective in the correction of skeletal class II patients. It produced a combination of skeletal and dental effects by forward movement of the mandible, palatal tipping of the upper incisors and labial flaring of the lower incisors. The addition of the acrylic capping to the lower incisors did not control the position of the lower teeth and did not prevent their labial flaring.