"Barb wire" redirects here. For other uses, see Barb wire (disambiguation).

A close-up view of a barbed wire

Roll of modern agricultural barbed wire

Barbed wire, also known as barb wire[citation needed], is a type of steel fencing wire constructed with sharp edges or points arranged at intervals along the strands. Its primary use is the construction of inexpensive fences, and it is also used as a security measure atop walls surrounding property. As a wire obstacle, it is a major feature of the fortifications in trench warfare.

A person or animal trying to pass through or over barbed wire will suffer discomfort and possibly injury. Barbed wire fencing requires only fence posts, wire, and fixing devices such as staples. It is simple to construct and quick to erect, even by an unskilled person.

The first patent in the United States for barbed wire[1] was issued in 1867 to Lucien B. Smith of Kent, Ohio, who is regarded as the inventor.[2][3] Joseph F. Glidden of DeKalb, Illinois, received a patent for the modern invention[4] in 1874 after he made his own modifications to previous versions.