Background Participation in social networking sites has considerable potential to leverage the individual's social capital, including persons with intellectual disabilities, whose real‐world social networks are fairly limited. Method This study aimed to understand how individuals with intellectual disabilities use Facebook to access social capital benefits, if at all. Qualitative interviews and observations were conducted with 20 adult Facebook users with intellectual disabilities. Results The online participation enhanced their bonding social capital as well as contributed to their psychological well‐being through increasing their online visibility, popularity and sense of belonging. At the same time, they experienced stress and frustration due to usage difficulties, which prevented them from enhancing their bridging social capital. Conclusions Participation in social networking sites may also leverage bridging social capital of persons with intellectual disabilities, but they need a more accessible platform and ongoing support to ensure safe and fruitful participation.