Ethnography is a branch of anthropology and the systematic study of individual cultures. Ethnography explores cultural phenomena from the point of view of the subject of the study. Ethnography is also a type of social research that involves examining the behavior of the participants in a given social situation and understanding the group members' own interpretation of such behavior.

As a form of inquiry, ethnography relies heavily on participant observation—on the researcher participating in the setting or with the people being studied, at least in some marginal role, and seeking to document, in detail, patterns of social interaction and the perspectives of participants, and to understand these in their local contexts. It had its origin in social and cultural anthropology in the early twentieth century, but spread to other social science disciplines, notably sociology, during the course of that century.

Ethnographers mainly use qualitative methods, though they may also employ quantitative data. The typical ethnography is a holistic study and so includes a brief history, and an analysis of the terrain, the climate, and the habitat. A wide range of groups and organisations have been studied by this method, including traditional communities, youth gangs, religious cults, and organisations of various kinds. While, traditionally, ethnography has relied on the physical presence of the researcher in a setting, there is research using the label that has relied on interviews or documents, sometimes to investigate events in the past such as the NASA Challenger disaster. There is also a considerable amount of 'virtual' or online ethnography, sometimes labelled netnography or cyber-ethnography.