A sit-in or sit-down is a form of direct action that involves one or more people occupying an area for a protest, often to promote political, social, or economic change. The protestors gather conspicuously in a space or building, refusing to move unless their demands are met. The often clearly visible demonstrations are intended to spread awareness among the public, or disrupt the goings-on of the protested organisation. Lunch counter sit-ins were a nonviolent form of protest used to oppose segregation during the civil rights movement, and often provoked heckling and violence from those opposed to their message.

Direct action is a term for economic and political behavior in which participants use agency—for example economic or physical power—to achieve their goals. The aim of direct action is to either obstruct a certain practice or to solve perceived problems.