This chapter examines the close relationships between the growth of new media technologies, including the internet, social media, and smartphones, and Korean politics. It analyses how the internet and social media have been influencing political messaging, voter behaviour, and the circulation of ideas in Korea, in which traditional media such as broadcasting and newspapers have played a major role in national politics, since the early 2000s onwards. It also explores how internet portals such as Naver and Daum (now Kakao) and mobile messaging services, such as KakaoTalk and Line, which account for over 70 per cent and 90 per cent of their respective markets, shape the political conversation and can act as gatekeepers for the circulation of ideas. Finally, it investigates whether the growth of these new media technologies has influenced people’s perceptions of politics and elections, which means that it discusses people’s use of new media technologies in their political practices.