Fire support is a military tactics term used to describe weapons fire used to support friendly forces by engaging, suppressing, or destroying enemy forces, facilities, or materiel in combat. It is often provided through indirect fire, though the term may also be used for some forms of supporting direct fire.

The United States Department of Defense defines fire support as "fires that directly support land, maritime, amphibious, and special operations forces to engage enemy forces, combat formations, and facilities in pursuit of tactical and operational objectives."

Fire support generally consists of fire from heavy or crew-served weaponry with high firepower, including strikes and barrages from artillery, mortars, rocket artillery, and missiles; naval gunfire support from naval artillery; airstrikes, strafes, and close air support from military aircraft; and drone strikes from unmanned combat aerial vehicles; among various other forms. Fire support is typically ordered and directed by an observer (e.g. artillery observer, forward air controller, etc.) on the front line, and provided by a weapon crew or operator in the rear, usually from a fortification, vehicle, or facility (such as a fire support base).

Fire support is used to support and supplement military units that may lack the capabilities or firepower offered by fire support. For example, an infantry unit needing heavy explosives to bombard an enemy emplacement, or a large smoke screen to cover their advance, and lacking the ability to do so themselves (e.g. insufficient effectiveness using grenades), may call for fire support from a capable nearby mortar unit.

Fire support can reduce friendly casualties whilst devastating enemy capabilities and morale. Effective use of fire support—as seen during the 2018 Battle of Khasham of the Syrian Civil War, where an outnumbered force used various forms of fire support to their advantage, avoiding serious casualties—may help swing a battle in one's favor.

Varying forms of fire support have existed since the advent of early cannons and rockets, which were used to bombard enemy positions and fortifications to support infantry. Warships have long provided fire support using their cannons. The use of fire support in its current form developed during World War I and World War II, when combined arms and advances in technology and tactics made fire support increasingly effective.

Fire support is defined as "assistance to infantry and armored units by artillery fire, naval gunfire, and airplane strafing and bombing."

Early versions of artillery included the Roman ballista, essentially a large, mounted version of a crossbow that fired a single arrow. The first documented use of bombards, (large mortars) in Europe as we know them today was at the siege of Algeciras in 1343. By the 1470s, casting and metal work dramatically improved, giving way to the modern cannon. In the early 15th century, cast iron balls were invented for cannons. These balls, combined with gunpowder, were commonly used during sieges. By around 1550, the French had begun categorizing their guns by caliber, leading to a more organized formation of artillery.