Lindon J. Eaves (born 23 September 1944) is a behavior geneticist who has published on topics as diverse as the heritability of religion and psychopathology. His research encompasses the development of mathematical models reflecting competing theories of the causes and familial transmission of human human differences, the design of studies for the resolution, analytical methods for parameter estimation and hypothesis-testing and application to substantive questions about specific (human) traits. He was the first to consider standardized variance components for heritability estimates and was the first (at least in the human context) to consider the effects of living with a relative (with a different genotype or, in the case of monozygotic twins, the same genotype) on the behavior of a person. Furthermore, he was the first to think about genotype x age interaction and set up the algebra to study the effects of genes working in males as well as females, making it possible to use twins pairs of opposite-sex (dizygotic opposite sex). Together with Nick Martin, he wrote many classical papers, one of which is "The genetic analysis of covariance structure". They also wrote the book, Genes, culture and personality: An empirical approach. In 2012, a Festschrift was held in Edinburgh dedicated to Eaves' work; the proceedings were subsequently published in Behavior Genetics.