The Panel Study of Income Dynamics (PSID) is a longitudinal, nationally representative survey of US fami-lies. The study began in 1968 and has collected 43 waves of data over 56 years on the original families and their descendants, and has added two major immigrant refresher samples in 19971999 and 20172019. PSID serves as a cornerstone for empirical social and behavioral research through its long-term measurement, over the life course and across generations, of economic, social, demographic, and health processes. The data are available free of charge to the research community, with outreach and support to new and established data us-ers. These features have led PSID to become one of the most widely used social science data sets in the world. The studys innovative design, broad content, and long duration have been central to understanding many key research and policy issues. The data support increasingly rich models of child and adult outcomes over the life course and across multiple generations of the same family. NICHD has co-funded the biennial Core PSID for each of the last 11 waves, from 2003 to 2023.