Survival knives are knives intended for survival purposes in a wilderness environment, often in an emergency when the user has lost most of their main equipment. Most military aviation units issue some kind of survival knife to their pilots in case their aircraft are shot down behind enemy lines and the crew needs tools to facilitate their survival, escape, and rescue. Survival knives can be used for trapping, skinning, wood cutting, wood carving, and other uses. Hunters, hikers, and outdoor sport enthusiasts use survival knives. Some survival knives are heavy-bladed and thick. Other survival knives are lightweight or fold in order to save weight and bulk as part of a larger survival kit. Their functions often include serving as a hunting knife. Features, such as hollow handles, that could be used as storage space for matches or similar small items, began gaining popularity in the 1980s. Custom or semi-custom makers such as Americans Gil Hibben, Jimmy Lile, Bo Randall, and Chris Reeve are often credited with inventing those features.

A knife is a tool or weapon with a cutting edge or blade, usually attached to a handle or hilt. One of the earliest tools used by humanity, knives appeared at least 2.5 million years ago, as evidenced by the Oldowan tools. Originally made of wood, bone, and stone, over the centuries, in step with improvements in both metallurgy and manufacturing, knife blades have been made from copper, bronze, iron, steel, ceramic, and titanium. Most modern knives have either fixed or folding blades; blade patterns and styles vary by maker and country of origin.