Data were collected from 385 students of Form 1 and Form 4 from Sekolah Menengah Kebangsaan in Kuala Lumpur and Selangor to explore the difference in their social networking sites (SNSs) usage in terms of time spent and login frequency. In particular, this study examined the associations between adolescents usage of SNSs and their face to face interaction with siblings and whether age did moderated this relationships. Hierarchical multiple regressions and simple slope analyses indicated that younger adolescents face to face interaction with siblings decreased the more time they spent on SNSs during school days and non school days. In addition, face to face interaction of younger adolescents with their siblings decreased the more frequent they logged on SNSs on non school days. These results suggested that age did moderated the relationships of adolescents SNSs usage to face to face interaction with siblings.