We investigate whether and how informal political talk on digital media contributes to citizens’ political participation with unique surveys based on samples representative of Internet users in seven Western democracies. We show that political talk on both social networking sites and mobile instant messaging platforms is positively associated with institutional and extra-institutional political participation. However, the relationship between talk on social networking sites and both types of participation is significantly stronger in established democracies (Denmark, France, United Kingdom, and United States) than in “third wave” democracies (Greece, Poland, and Spain). By contrast, the strength of the relationship between political talk on mobile instant messaging platforms and participation is not significantly different when comparing established and more recent democracies. These findings suggest that informal political talk on digital platforms can contribute to citizens’ participatory repertoires and that different institutional settings, in combination with different technological affordances, play an important role in shaping these patterns.