Youth parliaments have been conceived as means to reconnect young people with politics, give them a voice in public debates, and ultimately boost the legitimacy of parliaments as democratic institutions. However, to contribute to the overall quality of democracy, youth parliaments must also reflect certain democratic principles in their own organisation. This paper identifies five principles to assess the democratic credentials of youth parliaments: the quality of representation, quality of participation, openness of the agenda, meaningful impact, and enlightened understanding, and applies them to the Belgian Jeugd Parlement Jeunesse (JPJ). Our results show that the JPJ offers a safe space for open and respectful political discussion among youngsters, but faces difficulties in generating impact and guaranteeing representativeness among the participants. The latter limits the JPJ’s potential to close the widening gap between young people and politics.