Background: The motor impairment in cerebral palsy (CP) has an impact on posture and movement.  Motor function and general well-being in children with spastic diplegic CP depend on trunk control. Fully-immersive virtual reality (VR) training may be a valuable additional therapy for habilitation of trunk control and balance in children with diplegic CP. Purpose: This study aimed to explore the effect of fully-immersive VR training on trunk control and balance in children with diplegic CP. Patients and Methods: 30 children aged 6-8 years old with spastic diplegic CP were randomly assigned into 2 equal groups: Group (A) received traditional physical therapy exercises, and group (B) that received traditional program as the control group in addition to VR training, all participants received treatment for 12 weeks. Trunk control was evaluated using the Segmental Assessment of Trunk Control (SATCO) scale, while balance was examined using the Biodex balance system. Results: The post-treatment mean value of SATCO scale of group (A) was 17.13 ± 0.74 and that of group (B) was 18.27 ± 0.7. There was a notable difference between the both groups (p=0.001). The mean value of the overall stability measure of balance did not differ significantly between both groups post-treatment (p = 0.841). Conclusion: This study showed a positive effect of combined traditional physical therapy interventions with fully-immersive VR on trunk control in children with CP of spastic diplegic type. These findings highlight the importance of addressing combined techniques in the comprehensive management of children with CP.