Citizen Participation or Public Participation in social science refers to different mechanisms for the public to express opinions—and ideally exert influence—regarding political, economic, management or other social decisions. Participatory decision-making can take place along any realm of human social activity, including economic (i.e. participatory economics), political (i.e. participatory democracy or parpolity), management (i.e. participatory management), cultural (i.e. polyculturalism) or familial (i.e. feminism).

For well-informed participation to occur, it is argued that some version of transparency, e.g. radical transparency, is necessary but not sufficient. It has also been argued that those most affected by a decision should have the most say while those that are least affected should have the least say in a topic.