Gaiters are garments worn over the shoe and lower pants leg, and used primarily as personal protective equipment; similar garments used primarily for display are spats. Originally, gaiters were made of leather. Today, gaiters for walking are commonly made of plasticized synthetic cloth such as polyester. Gaiters for use on horseback continue to be made of leather.

In Army parlance, a gaiter covers leg and bootlacing; a legging covers only the leg. In RAF parlance, gaiter includes legging. The American Army during World War I and World War II had leggings, which were gaiters. Above the knee spatterdashes were cotton or canvas, as were many gaiters of varying lengths thereafter. Leather gaiters were rare in military, though sometimes a calf-length cotton gaiter had leather kneecaps added. Leggings, however, were very often made of leather, but also canvas.

Gaiters are a type of protective clothing for a person's ankles and legs below the knee. Gaiters are worn when walking, hiking, running (especially orienteering and rogaining) outdoors amongst dense underbrush or in snow, with or without snowshoes. Heavy gaiters are often worn when using crampons, to protect the leg and ankle from the spikes of the opposite foot. Gaiters strap over the hiking boot and around the person's leg to provide protection from branches and thorns and to prevent mud, snow, etc. from entering the top of the boot.