Online gaming has been the most rapidly growing segment of the video game market within the last ten years. Its market penetration has increased steadily attracting consumers worldwide. Even though, it occurs in a particular environment of competitive social networks, its adoption has gained only little scientific interest. To fill that gap, we suggest a model of online gaming adoption in competitive social networks. For that purpose, we combine the Theory of Planned Behavior with Social Network Theory, introducing external influences in terms of social interaction design and network exposure.