The growing use of social media like Facebook and Twitter is in the process of changing how news is produced, disseminated, and discussed. But so far, we have only a preliminary understanding of (1) how important social media are as sources of news relative to other media, (2) the extent to which people use them to find news, (3) how many use them to engage in more participatory forms of news use, and (4) whether these developments are similar within countries with otherwise comparable levels of technological development. Based on data from a cross-country online survey of news media use, we present a comparative analysis of the relative importance of social media for news in Denmark, France, Germany, Italy, Japan, Spain, the United Kingdom, and the United States, covering eight developed democracies with different media systems. We show that television remains both the most widely used and most important source of news in all these countries, and that even print newspapers are still more widely used and seen as more important sources of news than social media. We identify a set of similarities in terms of the growing importance of social media as part of people’s cross-media news habits, but also important country-to-country differences, in particular in terms of how widespread the more active and participatory forms of media use are. Surprisingly, these differences do not correspond to differences in levels of internet use, suggesting that more than mere availability shapes the role of social media as parts of people’s news habits.