With the project called: Sustainability and Quality of School Parliament Participation, we increased the quality and sustainability of school parliament activities in secondary schools. Quality and sustainability are the main themes of the workshop-discussion sessions, the outputs of which served to create the publication "#letsdevelop: Methodology for the development and sustainability of school parliaments as a way to youth participation." This publication will be a supporting methodological material for school parliaments in secondary schools. The project focused on meeting the EU Strategy's objective on youth participation. Workshop-discussion sessions were dedicated to the quality and sustainability of school parliaments and also to the development of inclusive approaches and environmental attitudes of school parliaments in their activities. The participating parliaments had the opportunity to practically verify the acquired competencies, which were focused on quality and sustainability. The validation was carried out through activities in a small project created by each school parliament involved in the project. In this way, they also extended their project management competencies. The outputs of the project were presented at the conference called Development and Sustainability of School Parliaments as a Way to Youth Participation. The main objective of the project was: to support the sustainability and development of school parliaments in secondary schools. The specific objectives were: 1/ to implement an increase in the level of education of new members of school parliaments in participation, inclusion and environmental issues, 3/ to apply the acquired knowledge in the implementation of participatory activities, 2/ to create methodological support for the development and sustainability of the active functioning of school parliaments and its public presentation.