Children with Autism Spectrum Disorder (ASD) or Hearing Loss (HL) have relationship challenges and mental health difficulties due to functional disturbance affecting social interaction. This study examined the role of Online Computer Game (OCG), and specifically Minecraft (MC), to facilitate social relations, mental health, and the wellbeing of children with ASD and/or HL in the United Kingdom (UK) and the Kingdom of Saudi Arabia (KSA). MC is a sandbox computer game in open-world format and recognised to be socially interactive gameplay, chosen here due to its popularity, accessibility and cooperative gameplay characteristics. In the first phase of this research, a systematic literature review was conducted of all peer-reviewed articles that were written in English and included first-hand evidence to synthesise the evidence for and against MC use in education (n=38). The review concluded MC to be beneficial to children regarding increased motivation for academic learning and social development including communication, sharing and collaboration skills. Therefore, the second phase was conducted to identify correlations between playing OCG or MC and children's social-emotional and behavioural outcomes, and specifically players' peer relationship problems using the convergent mixed methods design approach. Data consisted of three parts: questionnaire (n=255), interviews (n=7) and observations (n=4). Subjects for the questionnaire were parents of primary school children aged 8 and over from three groups: children with ASD (n=121), children with HL (n=11) and Typical Developing (TD) children (n=123). This thesis reported that MC is a social or entertaining activity that can be used as a place for social intervention for three reasons. First, cooperative gameplay on MC has no significant associations with difficulties on the SDQ for either TD or children with ASD in this research sample. Secondly, higher frequency of playing MC with others is associated with a lower peer relationship problems score in the KSA sample. Thirdly, the qualitative pieces of evidence show that the benefits outweigh the risks of playing MC, notably for children with ASD or HL. Therefore, MC might be potentially beneficial for social intervention for children with ASD or HL. Parents reported three main reasons for being interested in MC for children with ASD or HL: peer relationships and peer support (i.e., a space for social interaction with others), emotional benefits (e.g., enjoyment and being happy) and behaviour benefits (i.e.,being calm and relaxed or as a reward for desirable behaviours). Concerns about addiction, safety, and physical activity use were raised, but evidence shows that most of these concerns are related to gaming management rather than MC itself as a game. Concerns and thesis' limitations are discussed. Altogether, these data suggest that MC game-play may be considered appropriate for social interventions for children with ASD or HL, and may be considered for incorporation into educational pedagogy or psychological support for its social benefits. The study significantly added understanding of gaming and diagnostic condition characteristics in the role of peer relationship skills among children. The findings may help to advance current literature in the areas of children's social-emotional and behavioural development.