Journal ArticleWhen individuals disperse from one local group to another, they often do so in the company of relatives. This is known as "kin-structured migration," and its effect on genetic population structure is investigated here. It is shown that when migration is kin-structured, the ratio of between- to within-group variance is increased by a quantity that can be estimated either from behavioral or genetic data. Theoretical results indicate that kin-structured migration should be most important in populations with high mobility, and analysis of data for humans and lions suggests the kin-structured migration may have a substantial effect on genetic population structure in both species. Its effect seems to be small in a population of pine voles