A town square (or public square, urban square, city square or simply square), also called a plaza or piazza, is an open public space commonly found in the heart of a traditional town or city, and which is used for community gatherings. Related concepts are the civic center, the market square and the village green.

Most squares are hardscapes suitable for open markets, concerts, political rallies, and other events that require firm ground. They are not necessarily a true geometric square.

Being centrally located, town squares are usually surrounded by small shops such as bakeries, meat markets, cheese stores, and clothing stores. At their center is often a well, monument, statue or other feature. Those with fountains are sometimes called fountain squares.

The term "town square" (especially via the term "public square") is synonymous with the politics of many cultures, and the names of a certain town squares, such as the Euromaidan or Red Square, have become symbolic of specific political events throughout history.

Many cities in Australia's eastern states, such as Melbourne and Sydney, did not have a central town square in their design, due to a fear of rebellion. New South Wales Governors Richard Bourke and George Gipps notably ordered surveyors to not include a town square in city designs, including Melbourne, to prevent the spirit of democracy from arising.

The city centre of Adelaide and the adjacent suburb of North Adelaide, in South Australia, were planned by Colonel William Light in 1837. The city streets were laid out in a grid plan, with the city centre including a central public square, Victoria Square, and four public squares in the centre of each quarter of the city. North Adelaide has two public squares. The city was also designed to be surrounded by park lands, and all of these features still exist today, with the squares maintained as mostly green spaces.

In 2025, the City of Sydney council approved plans to accelerate the construction of a public square near the current Town Hall.

In China, People's Square is a common designation for the central town square of modern Chinese cities, established as part of urban modernization within the last few decades. These squares are the site of government buildings, museums, and other public buildings. One such square, Tiananmen Square, is a famous site in Chinese history due to it being the site of the May Fourth Movement, the Proclamation of the People's Republic of China, the 1976 Tiananmen Incident, the 1989 Tiananmen Square Protests, and all Chinese National Day Parades.