Research consistently document sport socialization as promising for the social skill learning in children with intellectual disability (ID).However, there exists limited evidenced based intervention research to confirm this research proposition. This study investigated the effectiveness of social skill training in a sport socialization intervention programme by gender in children with intellectual disabilities in Kenya. Objectives that guided the study was to compare rating of social behaviour levels across gender before and after the sport socialization intervention programme. Methodology: Intervention mode involved instructing, prompting, and cuing each child with ID into action and individualized guidance as supported by peers without disability. Single Subject (SSD) quasi-experimental research design was used. Data was collected at three weeks interval during baseline, Treatment and reversal treatment. Data collection instruments were 3-5 minute video capture, peer social task rating scale checklists Data analysis: Data was analyzed by visual analysis, time series analysis, video coding and Null hypotheses tested by Statistical Descriptive statistics was used in the discussion. Results: both boys and girls improved in all social tasks assessed after intervention. On social skill rating boys had an improvement range of 50%-62.3%, compared to the girls 56%-60%. Improvement was observed in all children irrespective of gender. Conclusion: the study concluded that the intervention programme was effective in enhancing social skill learning of Children with ID irrespective of gender. Gender did not affect social behavior responses at posttest. Sport socialization intervention programme affected the rate of social behavior functioning levels and should be enhanced in all children and Youth with ID in and out of school. The null hypothesis was neither retained nor rejected, since time series analysis test was not possible based on study design and mutual exclusivity of data points. Recommendations: the study recommended that boys and girls should be given equal opportunities to participate in sports and develop their social abilities. Finally the study recommended further research to be conducted on gender rating involving statistical analysis for confirmation of gender differences in social behavior functioning levels amongst children with intellectual disability.