Arnis, also known as Kali or Eskrima, is the national martial art of the Philippines. It is a form of martial art that focuses on weapon-based fighting with sticks, knives, bladed weapons, and different improvised weapons. It also includes techniques like hand-to-hand combat, grappling, joint locks, and weapon disarming. The name "Arnis" comes from "arnés," the Old Spanish word for "armour". It is said to derive from the armour costumes used in traditional Moro-moro stage plays, where actors fought mock battles with wooden swords. Arnes is also an archaic Spanish term for weapon, used as early as 1712. Eskrima (also spelled escrima) is derived from the Spanish word for fencing, esgrima.

Arnis was developed by the indigenous peoples of the Philippines, although the modern form is influenced by 15th-century Spanish fencing. In 1521, the use of Arnis was first recorded when the chieftain of Mactan, Datu Lapu-Lapu, and his tribesmen, equipped only with bladed weapons and fearsome Arnis abilities, successfully defeated the Spaniards and killed Ferdinand Magellan when they tried to invade. The Spaniards prohibited the traditions of Arnis when they successfully conquered parts of the Philippines, but it was still preserved with the use of sticks in the forms of ritual dance, performance, and mock battles.

Arnis techniques are generally based on the assumption that both student and opponent are very highly trained and well prepared. Thus, Arnis tends to favour extreme caution. In recent years, there has been increased interest in Arnis for its usefulness when defending against knives in street encounters. As a result, many systems of Arnis have been modified in varying degrees to make them more marketable to a worldwide audience. Usually, this involves increased emphasis on locking, controls, and disarms, focusing mainly on aspects of self-defense. However, most styles follow the philosophy that the best defense is a good offense.

Arnis was declared as the Philippines’ National sport and martial art on 11 December 2009. The first national organization for Arnis is the National Arnis Association of the Philippines (NARAPHIL) which was founded in 1975 by Gen. Fabian C. Ver.