This Element provides an overview of recent contributions to optimal tax theory across couple or family households.

This Element seeks to provide an in-depth survey of the papers written on the optimal taxation of the incomes of the members of family households, as opposed to households with just a single individual, over the period beginning with the early 1980s and ending in the late 2010s.This literature, solidly within the public finance tradition, is not large, and so the Element gives quite a full exposition and discussion of the main contributions. The papers are grouped according to the type of tax system they have dealt with: linear, piecewise linear and non-linear taxation.