Art Fair on the Square is an annual event held on the Capitol Square in Madison, Wisconsin, United States. The juried event brings together around 500 artists from across America on the second weekend of July. Most art forms are represented, including ceramics, glass, fibre arts, photography, graphic arts, sculpture, woodwork, metals and jewellery, as well as the traditional paint and print media. It has been one of the most popular events in Madison for 50 years, drawing an estimated 200,000 people each year, including artists, students, families and casual browsers. The event is organised by the Madison Museum of Contemporary Art (MMoCA) and serves as its primary fund-raising event. A virtual event was planned in 2020 as officials cited COVID-19 pandemic as cause.

As part of the art fair, the corners of the square and the middles of each side are lined with food vendors, music stages and other entertainment.