There is a growing realization that early life influences have lasting impact on brain function and structure. Recent research has demon- strated that genetic relationships in adults can be used to parcellate the cortex into regions of maximal shared genetic influence, and a major hypothesis is that genetically progr ammed neurodevel opmental events cause a lasting impact on the organization of the cerebral cortex observable decades later. Here we tested how developmental and lifespan changes in cortical thickness fit the underlying genetic organi- zational principles of co rtical thickness in a longitudinal sample of 974 participants between 4.1 and 88.5 y of age with a total of 1,633 scans, including 773 scans from children below 12 y. Genetic clustering of cortical thickness was based on an independent dataset of 406 adult twins. Developmental and adult age- related changes in cortical thick- ness followed closely the genetic organization of the cerebral cortex, with change rates varying as a functi on of genetic similarity between regions. Cortical regions with overlapping genetic architecture showed correlated development al and adult age change trajectories and vice versa for regions with low genetic overlap. Thus, effects of genes on regional variations in cortical thickness in middle age can be traced to regional differences in neurodevelopmental change rates and extrap- olated to further adult aging-related cortical thinning. This finding suggests that genetic factors contribute to cortical changes through life and calls for a lifespan perspective i n research aimed at identifying the genetic and environmental determinants of cortical development and aging. ; © National Academy of Sciences. This is the authors’ accepted and refereed manuscript to the article.