公共空间（又译公众场所、公众地方、公共场所；英文：public space或public place）是一个不限于经济或社会条件（纵然实际情况未必如此），任何人都有权进入的地方；譬如，人们不用缴费或购票进入，或进入者不会因背景受到歧视。共享空间是公共空间最早的例子。而类似「公共空间」的私营购物中心，就是「私人空间」（私人场所）的例子。

另外，从哲学、（城市）地理、视觉艺术、文化研究及社会研究等范畴来看，公共空间是关键性理论的某些标准。公共空间的定位似乎渐见迫切，因为资产涉及愈来愈多所谓「共享空间」。「公共空间」一词往往被人们误解，譬如与「集会场所」（gathering place）混淆，但这是一个较大概念的组成部分。

A public space is a social space that is generally open and accessible to people. Roads (including the pavement), public squares, parks and beaches are typically considered public space. To a limited extent, government buildings which are open to the public, such as public libraries are public spaces, although they tend to have restricted areas and greater limits upon use. Although not considered public space, privately owned buildings or property visible from sidewalks and public thoroughfares may affect the public visual landscape, for example, by outdoor advertising. Recently, the concept of Shared space has been advanced to enhance the experience of pedestrians in public space jointly used by automobiles and other vehicles.