Although economic hardship decreases children's well-being, little research has explored this association over time and whether parents’ and children's “linked lives” explain this association. Using the Child Development Supplement of the PSID (1997, 2002), this study explores how changes in economic hardship influence changes in children's well-being over a five-year time period. Results indicate that increases in economic hardship over time increase children's internalizing and externalizing problems, although stable high economic hardship is most detrimental for children's well-being. Parenting stress and parental well-being substantially explained these associations, illustrating how parents’ and children's “linked lives” influence the stress process for children.