## 1 Introduction  
Attention-Deficit/Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder characterised by persistent inattention, hyperactivity, or impulsivity that interferes with cognitive and social functioning [1]. ADHD is classified into three subtypes, based primarily on the presentation of symptoms. Individuals with the inattentive subtype may have difficulty maintaining attention, organizing tasks, following instructions, and completing assignments or activities [1]. Individuals with the hyperactive-impulsive subtype may frequently fidget, squirm, or feel restless and have difficulty staying seated, engage in excessive talking, and have a strong need for movement or physical activity [2]. Individuals with the combined subtype exhibit symptoms of both inattention and hyperactivity-impulsivity. This subtype often presents with a wide range of symptoms that can vary in severity [2]. Impaired social functioning can lead to inappropriate social interactions, poor peer relationships, and even peer rejection. Specific behaviours associated with social rejection among children with ADHD include aggression, explosiveness, inflexibility, control, bossiness, inattention during activities, and rule violations [2]. About 60% of children with ADHD experience peer rejection [3] because they are usually disliked in the initial social interaction [4], which results in reduction in future opportunities to practice social skills. Persistent peer rejection or social impairment is related to a significant risk for many unhealthy outcomes in adolescent development. Numerous studies have shown that social impairment is associated with depression and anxiety [5; 6]. Medication (e.g., methylphenidate) is the most effective way to manage ADHD-related symptoms by increasing the activities in the brain [7]. However, once patients stop taking the medication, the symptoms return [8]. It was found that these medications have side effects, including sleep problems, loss of appetite, headaches or stomach pains [9]. As a result, some parents may not provide medication for their children with ADHD [10]. In addition to medication, cognitive behavioural therapies such as social skill interventions are one of the common and widespread approaches for improving social skills among children with ADHD [11]. According to the meta-analysis of [PERSON] et al. [11], the forms of social skills intervention often include roleplays, games, and exercises performed individually or in small groups. These traditional approaches can offer real-life practice opportunities in a supportive environment [12]. Specific social skills can be taught to the children based on their unique needs and preferences. Immediate feedback can be provided by the instructors to allow the children better understanding of their improvement and weaknesses [13]. Even so, these traditional training approaches possibly bring some limitations to the learning process of children with ADHD, for instance, time and space constraints, and distractions caused by the environment. These children have symptoms of inattention; face-to-face training can easily be interfered with by other factors. Virtual reality (VR) has emerged as a promising tool for the rehabilitation of psychological disorders, such as ADHD, and for providing a safe and effective learning environment [14; 15]. VRs create a three-dimensional environment that allows users immersion and interaction with the virtual world [16]. Although numerous VR applications for children and adolescents with ADHD have been demonstrated [17; 18; 19; 15], these VRs are mainly used for enhancing attention, hyperactivity, impulsivity and executive functions in a safe environment. To the best of our knowledge, research on the use of VR to improve social skills in children with ADHD is limited. Yet, several studies assessed the efficacy of VR on social skills among children with autism spectrum disorder and intellectual disability and found better performance on social skills after VR-based interventions [20; 21; 22].