The fox in heraldry is a charge celebrated for its dual reputation as a symbol of wisdom, ingenuity, and wit used in self-defense, while also being tied to the cunning and stealth of the "sly fox" (Medieval Knight Shields). Traditionally, a fox is blazoned "proper" as gules (red) with an argent (white) tip to its tail, which is technically referred to in heraldry as its brush (Traceable Heraldic Art). Unlike the wolf, which often represents fierce military valor, the fox suggests a strategic mind—one that achieves its goals through intellectual sharp-wittedness and resourcefulness rather than brute strength.

In design, the fox appears in various attitudes, such as passant (walking), sejant (sitting), or salient (leaping), and its head is frequently depicted facing forward, a position known as cabossed or specifically a "fox's mask" (Traceable Heraldic Art). A specialty charge is the "fox ravishing a goose," a narrative image that highlights the animal's predatory nature and survival instincts. There are also mythological variations like the Sea-Fox, an aquatic monster with a fox's upper body and a fish's tail, often displayed in a naiant (swimming) or erect posture (Traceable Heraldic Art).

The fox is a prime candidate for canting arms, where the charge punningly represents the bearer's name; notable examples include the surname Fox in Ireland, which stems from the Chief of Teffia, dubbed "Sionnach" (The Fox), and the family of Leonhart Fuchs, whose surname is German for fox (Irish Surnames; Wikimedia Commons). Other historical examples include the arms of the Buxhoeveden family and various European towns like Cardeñosa de Volpejera in Spain, which features a fox in its civic achievement (Wikimedia Commons). For further visual reference, see the Foxes in Heraldry category on Wikimedia Commons.