Named in honour of George C. Williams, the Williams Revolution is a phrase used to characterise a paradigm shift asserted to have occurred in theoretical biology in the mid-1960s. Population genetics was largely the basis for the modern evolutionary synthesis and was described in terms of genes, verbal arguments were nearly always couched in terms of "survival of the species" — essentially group selection (a view notably expounded by V.C. Wynne-Edwards). This viewpoint was replaced by a gene-centered view of evolution, epitomised by kin selection. Models of the period showed that group selection was severely limited in its strength, although these models have since been shown to be too limited and newer models do admit the possibility of significant multi-level selection.

The book by Williams that was important in this process was Adaptation and Natural Selection (1966), though other researchers, including W. D. Hamilton, John Maynard Smith, and Robert Trivers , contributed to the shift in biological thinking at this time. Richard Dawkins popularised the revolution in his 1976 book, The Selfish Gene. The work can be seen as having built upon the work of Ronald Fisher as expressed particularly in his 1930 book, The Genetical Theory of Natural Selection.