Referendum campaigns, which happen in many countries on the national or sub-national level, are highly important and special periods of political communication. Unlike elections, however, referendum campaigns are understudied phenomena. This thematic issue addresses patterns of referendum campaigns, which increasingly take place in digital and hybrid media environments, where political actors conduct campaigns through various channels, news media react to and shape debates on social media, and citizens receive a large share of political information from traditional and digital media. In this editorial, we provide a short overview of how research on referendum campaigns has evolved and how it has started to shift its attention away from news coverage and toward the role of campaign actors and the citizens who use (or engage with) search engines and social media platforms. The articles in this thematic issue reflect this shift but also show that news media remain important actors in referendum campaigns. Finally, we outline further research steps, which should include even more holistic analyses of the hybridity of referendum campaigns and hopefully more comparisons across cases.