International audience Contrary to popular belief, the notion of well-being is not self-evident. It is a polysemic conceptthat evolves according to the different disciplines that studied it and which have, over the years,attempted to create indicators to either measure it or highlight its determinants. This article aimsto emphasise this multidimensional aspect. In order to do so, it will first review the plurality of itsdefinitions and measurements, their evolutions over the years, and what they owe to internationalorganisations. Then, it will highlight the many (unresolved) scientific debates that continue to surroundthis concept: how is it possible to capture well-being at individual and collective levels, andboth in an objective and subjective manner?KEYWORDS: well-being, definition, literature reviewCaisse nationale d'allocations familiales | « Revue des politiques sociales et familiales » 2021/4 n°141 | pages 231 à 240