Razor wire is a mesh of metal strips with sharp edges whose purpose is to prevent trespassing by humans. The term “razor wire”, through long usage, has generally been used to describe barbed tape products. Razor wire is much sharper than the standard barbed wire; it is named after its appearance but is not razor sharp. The points are very sharp and made to rip and snag clothing and flesh.

The multiple blades of a razor-wire fence are designed to inflict serious cuts on anyone attempting to climb through or over it and therefore also have a strong psychological deterrent effect. Razor wire is used in many security applications because, although it can be circumvented relatively quickly by humans with tools, penetrating a razor-wire barrier without tools is very slow and typically injurious, often thwarting such attempts or giving security forces more time to respond.