A survivalist is a person who anticipates a potential disruption in the continuity of local, regional or worldwide society, and takes steps to survive in the resulting unpredictable situation. Some survivalists take an interest in survival in the wilderness or at sea, while others look for opportunities to gain practice and training by assisting in government volunteer organizations. Still others look at historical incidents, either localized or affecting large regions, and put extra effort and funds into preparing themselves with all the tools and information needed to handle repeats of those same events.

Survivalists have current access to modern society, but prepare for a future loss. This differentiates them from other people who endure extreme situations by living in locations isolated through winter, incursion commandos and guerrillas, and from subsistence farmers.

The specific preparations made will depend on the nature of the anticipated disruption. The natures of the disruptions most commonly planned for among survivalists include:

1. Natural disasters, such as tornadoes, hurricanes, earthquakes, blizzards, and severe thunderstorms
2. Disasters brought about by the activities of humankind: chemical spills, release of radioactive materials, war.
3. Collapse of the socioeconomic structure resulting in the unavailability of electricity, fuel, food, water, and other goods and services. Concern over the Y2K computer bug led to a brief widespread interest in survivalism in 1999 for this reason.