Modern education systems evolve in a context of growing teacher shortages, frequent turnover and a low attractiveness of the profession. In such a context where these challenges interrelate, there is an urgent need to better understand the well-being of teachers and its implications on the teaching and learning nexus. This working paper proposes a comprehensive conceptual framework to analyse teachers' occupational well-being and its linkages with quality teaching. The core concept of this framework defines teachers' well-being around four key components: physical and mental well-being, cognitive well-being, subjective well-being and social well-being. The framework then explores how working conditions, at both system and school levels, can impact and shape teachers' well-being, both positively and negatively aspects. It also presents two types of expected outcomes regarding teachers' well-being: inward outcomes for teachers in terms of levels of stress and intentions to leave the profession; and outward outcomes on quality teaching in terms of classroom processes and student' well-being. In an annex, the paper proposes an analytical plan on how to analyse teachers' well-being indicators and cross the results with other OECD instruments. It also presents the field trial items of the new module on teachers' wellbeing which are included in the Programme for International Student Assessment (PISA) 2021 teacher questionnaire.