A hackamore is a type of animal headgear which does not have a bit. Instead, it has a special type of noseband that works on pressure points on the face, nose, and chin. Hackamores are most often seen in western riding and other styles of riding derived from Spanish traditions, and are occasionally seen in some English riding disciplines such as show jumping and the stadium phase of eventing. Various hackamore designs are also popular for endurance riding. While usually used to start young horses, they are often seen on mature horses with dental issues that make bit use painful, and on horses with mouth or tongue injuries that would be aggravated by a bit. Some riders also like to use them in the winter to avoid putting a frozen metal bit into a horse's mouth. In the Mexican Charro tradition, the Jáquima and Bozal substituted for the serrated iron cavesson used in Spain for training horses.

There are many styles, but the classic hackamore is a design featuring a bosal noseband, and sometimes itself called a "bosal" or a "bosal hackamore". It has a long rope rein called a mecate and may also add a type of stabilizing throatlatch called a fiador, which is held to the hackamore by a browband. Other designs with heavy nosebands are also called hackamores, though some bitless designs with lighter weight nosebands that work off tension rather than weight are also called bitless bridles. A noseband with shanks and a curb chain to add leverage is called a mechanical hackamore, but is not considered a true hackamore. A simple leather noseband, or cavesson, is not a hackamore; a noseband is generally used in conjunction with a bit and bridle. In 1844, Domingo Revilla defined and described the Jáquima and Bozal in Mexico, as follows:

“Jáquima is a kind of leather or horsehair bozal, secured with a harness of the same material, and at the base of the bozal that remains next to the horse's chin, there is a strap to further secure it, and it is called a fiador. The bozalillo is just the bozal without harness or without a fiador. There are very curious jáquimas and bozalillos, and both are very necessary for the horse.”

Like a bit, a hackamore can be gentle or harsh, depending on the hands of the rider. The horse's face is very soft and sensitive with many nerve endings. Misuse of a hackamore can not only cause pain and swelling on the nose and jaw, but improper fitting combined with rough use can cause damage to the cartilage on the horse's nose.