This article uses data from the 25,142-child study EU Kids Online to investigate the impact of sibling status on a child’s experience of online risk and opportunities. In general, the effects associated with having a sibling appear to be comparatively small. The presence of older siblings slightly increases use and skills, while younger siblings are associated with slight reductions. These dynamics are particularly visible in the use of social networking sites. Older siblings have the effect of increasing the range and number of online activities pursued by their younger siblings. Patterns around concerning exposure to risk and possible harm are not straightforward but younger children with an older sibling are not at an increased risk. Where younger aged children have even younger siblings, this is associated with a slight reduction in risk, whereas older-aged children with a younger sibling, and only children, appear to experience slight increases in risk.