An Anti-Tank Guided Missile (ATGM) or Anti-Tank Guided Weapon (ATGW) is a guided missile primarily designed to hit and destroy heavily armored tanks and other armoured fighting vehicles.

ATGMs range in size from shoulder-launched weapons which can be transported by a single soldier, to larger tripod mounted weapons which require a squad or team to transport and fire, to vehicle and aircraft mounted missile systems.

The introduction of smaller, man-portable ATGMs with larger warheads to the modern battlefield has given infantry the ability to defeat even heavily armored main battle tanks at great ranges, usually with the first shot. Earlier infantry anti-tank weapons such as anti-tank rifles, anti-tank rockets and magnetic anti-tank mines had limited armor-penetration abilities and/or required a soldier to approach the target closely.

First-generation manually command guided MCLOS missiles like the AT-3 Sagger require input from an operator using a joystick or similar device.

Second-generation semi-automatically command guided SACLOS missiles require the operator to keep the sights on the target until impact. Guidance commands are sent to the missile through wires or radio, or rely on laser marking or a TV camera view from the nose of the missile. Examples are the American TOW and Hellfire I missiles.

More advanced third-generation guidance systems rely on a laser or a camera, on the nose of the missile. Some of the latest models, such as the American Javelin, Indian Nag are "fire-and-forget". The Nag uses infra-red version and a millimetric wave (mmW) version.

Most modern ATGMs have shaped-charge high explosive (HEAT) warheads, designed specifically for penetrating armour. Tandem-charge missiles attempt to defeat very heavy or spaced vehicle armour by employing two separate warheads. Top-attack weapons are designed to focus the explosion down through an armoured fighting vehicle's thinner turret-roof or upper-hull armour.

Countermeasures against ATGMs include spaced, perforated, and composite armour, explosive reactive armour (ERA), jammers like the Russian Shtora, and active protection systems (APS) like Drozd and Arena.

Anti-tank weapons like bazookas and RPGs are not considered ATGMs since the projectile is unguided.