Experiencing various forms of economic hardship during childhood is associated with adverse developmental and health outcomes for children. Even though the economic and policy context may affect the association between economic hardship and children’s outcomes, most research has been done only in the U.S. and U.K.. Moreover, most research on economic hardship has focused only on income poverty, even though other dimensions of economic hardship – material hardship and poor housing quality – may also be associated with adverse effects on children and better capture children’s actual living conditions. This study aims to assess, the associations of income poverty, material hardship, and poor housing quality, with early childhood social-emotional and cognitive development, physical health, and sleep quality using longitudinal birth cohort data from France. France is a particularly interesting context to study these associations, having a non-negligible proportion of children living in poverty and a relatively generous welfare policy setting. We find that income poverty is the most common type of hardship, with about 13% of our sample experiencing this hardship. Most households in our sample experience no hardships (83%), or only one type of hardship (12%). However, a small proportion (5%) experiences more than one hardship. This study will use mixed-effects regression models to assess the association between the types and combinations of economic hardship and children’s outcomes. Results will be placed within the international literature and interpreted in light of the policy context of France.