An anti-personnel weapon is a weapon primarily used to maim or kill infantry and other personnel not behind armor, as opposed to attacking structures or vehicles, or hunting game. The development of defensive fortification and combat vehicles gave rise to weapons designed specifically to attack them, and thus a need to distinguish between those systems and ones intended to attack people. For instance, an anti-personnel landmine will explode into small and sharp splinters that tear flesh but have little effect on metal surfaces, while anti-tank mines have considerably different design, using much more explosive power to effect damage to armored fighting vehicles, or use explosively formed penetrators to punch through armor plating.

Many modern weapons systems can be employed in different roles. For example, a tank's main gun can fire armor-piercing ammunition in the anti-tank role, high-explosive ammunition in the anti-structure role and fragmentation shells in the anti-personnel role.

There are also more exotic classes of weapons, such as neutron bombs, chemicals, and biological weapons, which are only designed to attack people. As there is a greater international criticism of them, they are therefore rarely used. These are not generally referred to as anti-personnel weapons but by their own names or group terms (e.g., NBC weapons) by which they are specifically banned. Such weapons often create much collateral damage and may affect large numbers of civilians, as well as causing long spanning consequences when they are not detonated in the case of buried explosives.