A fence is a structure that encloses an area, usually outdoors, and is usually constructed of columns connected by planks, wires, rails, or netting. The difference between fence and wall is that fence has no solid foundation in the whole length.

Alternatives to fencing include ditches (sometimes filled with water to form moats).

Fences can be the source of heated disputes between neighbors, and there are often special laws to solve these problems. Common differences include what kind of fence is needed, what kind of maintenance is needed and how to share the cost.

In some legislatures, the standard height of the fence is limited and special permission is required to exceed that height.