A platform cooperative, or platform co-op, is a cooperatively owned, democratically governed business that establishes a two-sided market via a computing platform, website, mobile app or a protocol to facilitate the sale of goods and services. Platform cooperatives are an alternative to venture capital-funded platforms insofar as they are owned and governed by those who depend on them most—workers, users, and other relevant stakeholders.

Platform Cooperativism is an intellectual framework and movement which advocates for the global development of platform cooperatives. Its advocates object to the techno-solutionist claim that technology is, by default, the answer to all social problems. Rather, proponents of the movement claim that ethical commitments such as the building of the global commons, support of inventive unions, and promotion of ecological and social sustainability as well as social justice, are necessary to shape an equitable and fair social economy. Platform cooperativism advocates for the coexistence of cooperatively owned business models and traditional, extractive models with the goal of a more diversified digital labor landscape respecting fair working conditions.

Platform cooperativism is not exactly about digital disintermediation, since a coop, which is a legally constituted moral entity, owns the digital platform. It is different from platform corporations like Uber, in that the governance of the digital platform is democratic. There are some similarities with the peer-to-peer production movement, influenced by Michel Bauwens and the P2P Foundation, which advocates for "new kinds of democratic and economic participation" as far as it is concerned with "the free participation of equal partners, engaged in the production of common resources". Economically and institutionally it is more distant from the radically distributed, non-market mechanisms of commons-based peer production promoted by Yochai Benkler., although they share some ethical considerations. Marjorie Kelly's book Owning Our Future contributed the distinction between democratic and extractive ownership design to this discussion.

While platform cooperatives are structured as cooperatives, granting democratic control to workers, customers, users, or other key stakeholders, companies and initiatives that support the ecosystem of the cooperative platform economy are considered a part of the platform cooperativism movement insofar as they attempt to encourage, develop, and sustain its development. It has also been argued that, as the spread of platform cooperativism "will require a different kind of ecosystem—with appropriate forms of finance, law, policy, and culture—to support the development of democratic online enterprises".

While there is no commonly accepted typology of platform cooperatives, researchers often categorize platform cooperatives by industry. Some potential categories include: transportation, on-demand labor, journalism, music, creative projects, timebank, film, home health care, photography, data cooperatives, marketplaces. Other typologies differentiate platform cooperatives by their governance or ownership structures.

Platform cooperatives are a business model that differs from platform capitalism, prioritizing fairness and sharing over profit motive. On the other hand, platform capitalists, such as Airbnb and Uber, are more traditional multi-sided businesses focusing on profit and returns to investors. These can also be referred to as capitalist platforms, while cooperativist platforms prioritize cooperation and fairness in addition to a profit motive.

Projects like Wikipedia, which rely on unpaid labor of volunteers, can be classified as commons-based peer-production initiatives, which are distinct from platform cooperatives since they don't employ the same institutional framework and governance.

Many platform co-operatives use business models similar to better-known apps or web services, but with a cooperative structure. For example, there are numerous driver-owned taxi apps that allow customers to submit trip requests and notify the nearest driver, similar to Uber.