Most research concerned with students' civic learning has focused on what has been learnt as a result of their school experiences. While some attention has been paid to the influence of parents, peers and out-of-school experiences, in general these influences have been regarded as marginal to those provided by the official curriculum. While we do not underestimate the importance of these latter experiences, our focus in this chapter is on informal learning and its impact on the development of student's civic knowledge. Student samples from Hong Kong, Korea and Taiwan were drawn from the International Civic and Citizenship Education Study (ICCS) 2016. Informal learning was defined in the study reported here as “traditional media,” “social media” and “interaction with friends.” Structural equation modelling was used to test the relationship between informal learning, formal learning, citizenship self-efficacy, participation experiences and civic knowledge. Results indicated that traditional media exerted a positive effect on students' civic learning across the three societies; social media exerted a small but negative effect in all societies, though the effect was not significant in Korea. Talking with friends about social and political issues or about other countries, as a source of informal civic learning, did not affect students' civic knowledge in any significant way in any society. Copyright © 2020 selection and editorial matter, Javier Calvo de Mora and Kerry J. Kennedy; individual chapters, the contributors.