Democratic deliberative theory has long emphasized the importance of citizen deliberation as a form of political participation and a centrally important component of any vital democracy. Public deliberation and discourse among citizens has been less frequently investigated as a form of political participation than more standard indicators such as voting or volunteering for political organizations. This research examines the extent to which internalized beliefs about deliberation are associated with deliberation outcome measures among a national sample of high school students participating in a year-long deliberation forum, Project 540. Using a multilevel analysis, the research specifically tested the extent to which scales of personal and normative deliberation beliefs, independently and moderated by Project 540 participation, predict key deliberative outcomes (e.g., civic skills, intention to participate in civic affairs). We find that predeliberation endorsement of both personal and normative beliefs predicts increases in certain positive deliberative outcomes, and that these effects are not moderated by participation in Project 540. The implications of these findings for deliberative democracy theory and for developing effective citizen deliberation forums are discussed.