The ovoo is a traditional monument originally associated with the cult of Sacred Mountains and the sky. It typically takes the form of a stone cairn and is found at the summit of hills and mountains, or any other elevated location.

In regions where stones are scarce, the ovoo can be constructed from sand, earth, or tree branches. While many ovoos are simply built as markers at mountain passes, most are considered sacred monuments.

A Mongolian should never pass by a sacred ovoo without stopping. They must dismount their horse and make an offering to the ovoo—either by placing money on it, sprinkling it with vodka or dairy products, or cutting a few hairs from their horse's tail and tying them to the ovoo. They must also add a stone.

The ovoo plays a crucial role in sacrifice ceremonies. Generally, ovoo worship takes place at the end of summer. During veneration, three branches are placed on the ovoo and prayer flags, made from cloth or paper inscribed with religious texts, are tied to them. On or near the ovoo, the faithful burn juniper as incense in a row of 3 stones leading to each of the four sides of the structure. A fire is lit on or near the summit of the ovoo, and the faithful then make their offerings of meat, dairy products, vodka, or airag. A shaman will then perform a dance or lamas will conduct a reading, with the faithful sitting to the northwest of the ovoo (in recent times, the growing involvement of monks in blessing ovoos has significantly reduced shamanic participation in this ritual). Once the ceremony concludes, the faithful share the remaining meat and dairy products, leaving a portion for the ovoo. The Naadam Festival has long been associated with an ovoo veneration ceremony.