The abilities of citizens to make themselves heard and listen to each other are essential for the functioning of democratic societies. Schools are practice grounds for these citizenship competences. This study investigates whether students' experiences with voice in school are related to their attitudes towards voice (contributing and listening democratically), and how a democratic school culture affects this relation. Overall, 5297 students, from 240 classrooms, in 81 Dutch secondary schools, participated in the study. Results of multilevel analyses revealed that students' voice experiences at school, their own and those of their classmates, are positively related to students' attitudes towards contributing and listening democratically. This relation is not affected by a democratic school culture. These findings underline the relevance of opportunities to practice voice at school for all students and of the social nature of practicing voice. More generally, this study illustrates the importance of understanding schools as practice grounds for citizenship.