Khutugtu Khan (Mongolian: Хутагт Хаан; Chinese: 庫圖克圖汗), born Ligdan (Mongolian: Лигдэн; Chinese: 林丹), (1588–1634) was a khagan of the Northern Yuan dynasty, reigning from 1604 to 1634. During his reign, he vigorously attempted to reunify the divided Mongol Empire, achieving moderate levels of success. However, his unpopular reign generated violent opposition due to his harsh restrictions over the Mongol tribes as he attempted to centralize the state. His alliance with the Ming dynasty, sponsorship of Tibetan Buddhism in Chakhar and the reorganization of Mongol political divisions were ineffective when the Later Jin dynasty became the major power in East Asia.

His name is from Mongolian "Ligden Khutugt Khan" (Mongolian Cyrillic: Лигдэн Хутугт хаан), title Ligden Khutugt from Standard Tibetan: རྦད་དེ་ཐོག་ཐུ།.

His name is also written Lindan Han (Chinese: 林丹汗; 1588–1634).

Ligden (b. 1588) was a son of Mangghus Mergen Taiji and grandson of Buyan Sechen Khan (r. 1593–1603). Because his father died early, Ligden was chosen to succeed his grandfather Buyan as khan of the Northern Yuan dynasty with the reign title Khutugtu in 1603. At the time the Khagan's appanage, Chakhar people, occupied Sira Mören valley. Ligden divided the Chakhar into right and left wings and built Chaghan city near Abaga Khara Mountain.

During his early reign, Ligden had the respect and loyalty of other Mongol tümens. Boshigo jinong of the Three Right Wing Tumens expressed his allegiance to Ligden Khan. Allied with princes of the Southern Khalkha (Baarin and Jarud), Ligden raided the Ming dynasty. However, from 1612 on, leaders of the Khorchin and the Jarud became in-laws with the rising Manchu-led Later Jin dynasty. By the early 17th century, the Khan's court had lost most of its power and was under pressure from the Manchus in the east. Hoping that he could consolidate his power over the Mongol tümens, Ligden moved the Buddhist religious center of the Mongols to Chakhar and had himself declared both religious and political leader of the Mongols by a Tibetan religious leader. Ligden revived the old Saskyapa order of Kublai's time (r. 1260–94), inviting the order's Sharba pandita, who was appointed his preceptor in 1617. Sharba installed Mahakala image in Ligden's capital Chagan. Ligden Khan also built temples at Küriye.

In 1618, Ligden signed a treaty with the Ming dynasty to protect their northern border from the Manchus in exchange for thousands of taels of silver. He received an annual subsidy of 40,000 taels of silver in 1620. Sog Zaisai, a Southern Khalkha nobleman, prince Sanasarai of the Khorchin, and Paghwa of the Jarud attacked the Later Jin with more than 10,000–50,000 men to assist the Ming in August 1619, but they were crushed. Because the Later Jin wanted to use the Mongols against the Ming, they persuaded their leaders, including Ligden, to ally with them. Since a conflict with the Later Jin in 1619, the relations between his clan federation and the Manchu federation had continuously deteriorated. In 1620, after an exchange of contemptuous letters, Ligden and the Later Jin ruler Nurhaci (r. 1616–1626) broke off relations and most of the Eastern Tümens deserted to Nurhaci in 1622–24.

Ligden, on the other hand, by trying to assume this former power, ruled in a progressively aggressive fashion, so several Mongolian tribes opted to form a coalition with the Manchus. When the Khorchin and some formerly allied tribes bonded with the Manchus in 1624, Ligden undertook a punitive expedition and besieged the Khorchin nobleman Oba for 3 days, but retreated when Manchu relief troops arrived. When Ligden Khan called the northern Khalkhas to join him against the Manchus, only Tsogt Taij accepted his appeal.

Ligden aimed at centralizing Mongol rule. He appointed officials to rule the left and right wing tümens, and organized a special court nobility and a corps of 300 baaturs (warriors). In 1627, the other tümens were in full revolt. Princes ruling the Sunid, Uzemchin, and Abaga moved northwest and allied with the Three Right Wing Tumens against Ligden. They attacked Ligden at Zhaocheng. Ligden defeated the allies but lost 10,000 Chakhars. When the Ming court refused to pay subsidy, he raided the Ming Empire, forcing them to renew the treaty. The Ming increased his annual subsidy to 81,000 taels of silver. In 1631 Ligden passed the Khinggan Range and successfully attacked the Khorchin and the Tümed. A powerful alliance of Khorchin, Tümed, Yungshiyebu, Ordos and Abaga was formed against Ligden. They destroyed 4,000 Chahar militias in Hohhot and 3,000 soldiers who were going to take Ligden's subsidy from the Ming. In 1632, the Later Jin khan Hong Taiji and his Mongol allies undertook a campaign against Ligden who avoided a confrontation and with maybe 100,000 Chakhar fled to Kokenuur. Ligden made himself yet more unpopular by seizing the wife of Erinchin jinong and taking refuge in the Eight White Yurts of Genghis Khan in Kokenuur. Allied with the Tibetan monarchs, he opposed Dalai Lama V and Banchin Erdene IV. He died of smallpox at Sira Tala (in modern Gansu) in 1634 while marching to attack dGe-lugs-pa order (Yellow Hat sect) in Tibet.