In this introduction to the special issue Contesting the Mainstream: Understanding Alternative News Media and its Contribution to Diversity, we discuss how and to what extent alternative news media contribute to news diversity. We elaborate on the concept of diversity, the democratic role of media and the normative implications of the position of alternative media in the wider media sphere. Based on the articles published in this special issue, that offer new and revealing empirical insights into a wide range and diversity of alternative media sites and their practices from Europe, Asia, the Middle East, North America, and Latin America, we argue that it becomes increasingly clear that awareness about normative positions within alternative ...