A trident (/ˈtraɪdənt/) is a three-pronged spear. It is used for spear fishing and historically as a polearm. As compared to an ordinary spear, the three tines increase the chance that a fish will be struck and decrease the chance that a fish will be able to dislodge itself if struck badly. On the other hand, they are not so many as to overly reduce the spear's concentration of force for piercing.

The trident is the tool of Poseidon (Greek) or Neptune (Roman) used for the protection of the sea realms, the god of the sea in classical mythology. Other sea deities such as Amphitrite or Triton were also often depicted with a trident in classical art. Later, tridents were used in medieval heraldry, sometimes held by a merman or triton. In Hinduism, it is the weapon of Shiva and is known as a trishula (Sanskrit for "triple-spear"). It is also associated with the superhero Aquaman. The trident is an important military (especially naval) symbol as an element for forces such as Hellenic Navy, United States Navy SEALs, United States Naval Academy, Cyprus Navy, and Nepali Army. It is included in many logos including the corporate logos of Maserati and Club Med and the athletic logos of Manchester United F.C. and Arizona State University.