Involving young people in the co-production of whole-school wellbeing strategies is aligned with the United Nations rights of the child and current UK legislation. This exploratory participatory action research (PAR) project aimed to facilitate teacher-student collaboration in one high school to develop whole-school practice with a focus on assessment. Training videos were co-created focusing on students' assessment experiences and ways to improve wellbeing and performance. Reflexive thematic analysis of the data identified key facilitators and challenges to the PAR process, alongside insights into students' assessment experiences. The paper concludes that PAR has the potential to empower young people and open channels of communication between students and teachers. Implications for educational psychology (EP) practice and future research are discussed.