Schools represent an important context for implementing participation rights guaranteed by the United Nations Convention on Rights of the Child into the lives of children in general and into the lives of children from vulnerable groups. Providing opportunities for children to exercise their participation rights has been linked to positive youth development and universal prevention efforts in schools. Available evidence points to the importance of beliefs regarding children’s agency and participation practices. This study extends available research by investigating elementary-, middle- and high-school teachers’ beliefs about children’s participation rights and their link to participation conducive teacher practices in schools. A comprehensive mediational model is tested, which posits that teachers’ image of children as capable, active and agentic is associated with more support for children’s participation rights, which in turn predict student-centered participatory teaching and classroom management behaviors. Teachers’ support for participation rights was measured using contextualized vignettes including both general situations and situations specific to children from vulnerable groups. A total of 519 elementary, middle and high-school teachers completed several online questionnaires. Results showed that teachers have an ambivalent image of children’s capacity and agency for decision- making, and that this view does not depend on the children’s age. Having a more positive image of children and supporting children’s participation rights more predicted student-centered teaching style and less controlling classroom management styles. Support for children’s participation rights was a significant mediator of the relationship between the teachers’ image of the children and their participation-fostering classroom practices. These findings have important practical implications for school climates which promote high-quality teaching, the prevention of problem behaviors and positive youth development.