Social media have increasingly been recognized as an important and effective tool for advocacy. A growing body of research examines the use of social media in grassroots and social movements as well as issues related to civic engagement, social capital, and voter turnout. The extent to which organized interest groups have adopted social media as an advocacy tool, however, has been relatively ignored. This article examines the determinants of the use of social media tools by a broad range of interest organizations. We argue that social media use needs to be understood as part of an interest organization’s larger set of news media lobbying strategies. We explain social media use as a function of two factors: first, the importance organizations place on trying to shape lobbying debates through the news media; second, the importance they place on shaping their public image via the news media. We test this argument using a unique data set of interest group advocacy in the European Union. Controlling for a host of competing explanations, regression results provide evidence supporting our central argument.