In sociology, social distance describes the distance between individuals or social groups in society, including dimensions such as social class, race/ethnicity, gender or sexuality. Members of different groups mix less than members of the same group. It is the measure of nearness or intimacy that an individual or group feels towards another individual or group in a social network or the level of trust one group has for another and the extent of perceived likeness of beliefs.

Modern research into social distance is primarily attributed to work by sociologist Georg Simmel. Simmel's conceptualization of social distance was represented in his writings about a hypothetical stranger that was simultaneously near and far from contact with his social group.

Simmel's lectures on the topic were attended by Robert Park, who later extended Simmel's ideas to the study of relations across racial/ethnic groups. At the time, racial tensions in the US had brought intergroup relations to the forefront of academic interest. Robert Park tasked his student, Emory Bogardus, to create a quantifiable measure of social distance. Bogardus' creation of the first Social Distance Scale played a large role in popularizing Park's and Bogardus conceptualization of social distance, which had some significant differences from Simmel's original ideas.

Contemporary studies of social distance do exhibit some features of a cohesive body of literature, but the definitions and frameworks sometimes show significant variations across researchers and disciplines.

Nedim Karakayali put forth a framework that described four dimensions of social distance:

It is possible to view these different conceptions as "dimensions" of social distance, that do not necessarily overlap. The members of two groups might interact with each other quite frequently, but this does not always mean that they will feel "close" to each other or that normatively they will consider each other as the members of the same group. In other words, interactive, normative and affective dimensions of social distance might not be linearly associated.

Some ways social distance can be measured include: direct observation of people interacting, questionnaires, speeded decision making tasks, route planning exercises, or other social drawing tasks (see sociogram).

Bogardus Social Distance Scale and its variations remain the most popular measure of social distance. In questionnaires based on Bogardus' scale, respondents are typically asked members of which groups they would accept in particular relationships. For example, to check whether or not they would accept a member of each group as a neighbor, as a fellow worker as a marriage partner. The social distance questionnaires may not accurately measure what people actually would do if a member of another group sought to become a friend or neighbour. The social distance scale is only an attempt to measure one's feeling of unwillingness to associate equally with a group. What a person will actually do in a situation also depends upon the circumstances of the situation.