Social organisation or social institution, is a group of social positions, connected by social relations, performing a social role. It can be also defined in a narrow sense as any institution in a society that works to socialise the groups or people in it. Common examples include education, governments, families, economic systems, religions, and any people or groups that you have social interaction with. It is a major sphere of social life organised to meet some human needs.

Social organisations can take many forms, depending on the social context. For example, for family context the corresponding social organisation is the extended family. In the business context a social organisation may be an enterprise, company, corporation, etc. In the educational context, it many be a school, university, etc. In the political context it may be a government, political party, etc. Commonly, experts officially recognise these five major social institutions that have been evident in some way in every civilisation in history: government, religion, education, economy, and family.

To give a simple example: productive institutions are dependent on educational institutions for a skilled workforce, educational institutions are dependent on the government for their funding, and government institutions, in turn, rely on productive institutions to create wealth to finance government spending. Sociologist call this institutional interdependence.

Max Weber concluded that in the history of mankind, organisations evolved towards rationalisation in the form of a rational-legal organisation, like bureaucracy.