土司是中国边疆的官职，元朝始置，用于封授给西北、西南地区的少数民族部族头目。

受中国文化的影响，越南后黎朝和阮朝也在其北部少数民族山区设立土司制度，委任部族首领进行统治。

土司职位可以世袭，但是袭官需要获得朝廷批准。元朝的土司有宣慰使、宣抚使及安抚使三种武官职务。《明史·职官志一》：“凡土司之官九级，自从三（从三品）之袭替，胥从其俗。附寨之官，自都督至镇抚，凡十四等，皆以诰敕辨其伪冒。”

明朝与清朝沿置土司，自明朝起，增加了土知府、土知州、土知县三种文官职务。土司对朝廷承担一定的税金、劳役、并按照天子朝廷的敕令提供军队；对内维持其作为部族首领的统治权利。明孝宗弘治五年（1492年）设置广西庆远府永顺正长官司。共十九任世袭长官，至清宣统二年（1910年）实行改土归流，历时408年。土司恣意虐杀土民时有所闻，被杀害的家属，还要征收银两，名之曰“玷刀钱”。永乐十一年，思南宣慰使田宗鼎与思州宣慰使田琛因争地叛乱，互相厮杀。乱事平定后，于当地设置贵州布政使司，揭开改土归流的序幕。播州之役后，明朝政府于万历二十九年（1601年），以播州宣慰司设遵义、平越二府。遵义府入隶四川，平越府入隶贵州。

Tusi (tu-szu), also known as Headmen or Chieftains, were tribal leaders recognized as imperial officials by the Yuan, Ming, and Qing-era Chinese governments, principally in Yunnan. The arrangement is generally known as the Native Chieftain System.

The system originated from Yuan accommodations following the conquest of Dali in AD 1253 by Mongol forces under the command of Kublai, the brother of the Great Khan. The former ruling Duan dynasty were appointed as its governors general. and local leaders coöpted under a variety of titles as administrators of the region. Some credit the Turkoman governor Shams al-Din with introducing the components of the system. Duan Xingzhi, the last king of Dali, was appointed as the first local ruler, and he accepted the stationing of a pacification commissioner there. After Kublai's departure, unrest broke out among certain factions. In 1255 and 1256, Duan Xingzhi was presented at court, where he offered the Yuan Emperor Mengu maps of Yunnan and counsels about the vanquishing of the tribes who had not yet surrendered. Duan then led a considerable army to serve as guides and vanguards for the Mongolian army. By the end of 1256, Uryankhadai had completely pacified Yunnan. In 1381, the Ming Emperor Zhu Yuanzhang sent a force against the last remnant of the forces of the Yuan Dynasty, led by the Prince of Liang Basalawarmi, who committed suicide. This left Duan Gong, a successor of Duan Xingzhi, as the last representative of remnant Yuan forces. He refused to surrender and attempted to have the former Dali kingdom recognized as a tributary state. When defeated in battle, the surviving Duan brothers were taken captive and escorted in to the capital. There they were given an insignificant office in the interior. From then on, "permanent chieftains were replaced by transferable officials," formally appointed by the Ming court.