A crisis is a situation which is difficult, unexpected, or an emergency. It is often an important "turning point", where a decision must be taken, affecting many people. Very often, this decision must be taken in relatively little time. The word is related to the Greek κρίσις (krisis). Examples include the sudden threat of war, or the occurrence of a natural disaster.

According to Steven Fink, a crisis manager, crises may:

1. be difficult to control
2. the focus of mass media, or government attention
3. interfere with regular business