A howitzer or hauwitzer is a type of field artillery. The name derives from the Czech word houfnice, denoting a 15th century cannon used by Hussites during the Hussite Wars. Howitzers are distinguished from other types of cannon artillery by their trajectory in that they tend to fire at high angles and deliver plunging fire. In addition to this, the barrel of a howitzer is commonly below 30 calibers (the length of the barrel is less than 30 times as long as the diameter of the bore), whereas other cannon and field guns tend to fire at no more than 45° and have a caliber of 30 or over. Development of the gun-howitzer, a weapon that can fire at both high and low angles was continued after the Second World War. With much longer barrels than howitzers, barrel lengths of 39, 45 or longer are now common, they have replaced separate guns and howitzers on the battlefield.

Howitzers are still either towed, or now self-propelled where they mix the maneuverability and to some extent the protection of tanks with their heavy firepower. Small howitzers can be towed by a light vehicle or carried by helicopter. Most are towed by five-ton or larger trucks. The "pack" howitzer (such as the 25 Pounder Short Mark 1) has existed since before the First World War. It can be disassembled into several main components and carried by mule through very difficult terrain, although the gun size is still a limiting factor and smaller howitzers have generally been abandoned in favor of larger guns with greater capabilities.

Modern self-propelled howitzers such as the South African G6 fire 105 to 155 mm diameter shells up to about 25–30 km at a maximum rate of about 10 per minute.