The epic of Jangar or Jangar epic (Kalmyk: Җаңһр, romanized: Cañhr, [d͡ʒaŋɣər]; Mongolian: ᠵᠢᠩᠭᠠᠷ, Жангар, romanized: Jangar, [d͡ʒɑŋɢər]) is a traditional oral epic poem (tuuli) of the Mongols. It was long thought to be particular to the Kalmyks, but is now known to also be widely told among the Oirats in Mongolia, China and Russia. The story is recited by singers called Jangarchi (Kalmyk: Җаңһрч, romanized: Cañhrç, [d͡ʒaŋɣərt͡ʃə]). The Jangar has approximately 25 or 26 chapters, though certain versions may have more than 100 chapters.

The epic begins by recounting the story of Jangar's great-grandfather, Tahil Zul Khan, who is kind and honest. Tahil Zul Khan leads his people to a land called Bomba where he hoped to create a place where they would be no suffering or death. His tribe settles in Bomba and after 10 years of struggle, they manage to build a paradise there. However, one day Tahil Zul Khan goes to check on his horse herd and a blizzard strikes, forcing him to take refuge in a valley. When the blizzard finally waned after several days, he tried to leave, only to be buried by an avalanche.

Tangsag Bumva, his son, becomes Khan. Also noted for being kind and wise, he tries to do what his father has done, but is thwarted by years of bad weather that kills half the tribe's livestock. Eventually Tangsag Bumva Khan dies of overwork, and his 12-year-old son Ujung Aldar becomes Khan. Ujung Aldar is Jangar's father.

One day Ujung Aldar was participating in a horse race with some other youths for the prize of an iron-gray horse. However, as he rode past a hill, he came to a lake and stopped to watch a pair of swans courting. Fascinated by their love, he watched them until they flew away. Afterwards, he found himself feeling lonely and sad. His advisor, Master Choirom, suggested that he take a wife, and mentioned a 16-year-old girl named Urmaa in the tribe of Dorj Khan in the south. Ujung Aldar was pleased at the prospect, so Choirom went to Dorj Khan to arrange the match. Dorj Khan was agreeable, so Ujung Aldar Khan went to the south to be married, bring with him betrothal gifts. After drinking 75 cups of liquor and 75 cups of fermented milk with Dorj Khan, Ujung Aldar Khan left the party and went to the tent where his bride Urmaa was. In accordance with custom, the other members of Urmaa's family playfully tried to stop him, and he had to force, argue, and persuade his way through to the bride's yurt. At last he managed to break through and go in and get his wife. He put her on his great red stallion, Aranjagaan, and they galloped to the bridal yurt. Afterwards they returned to Bomba together.

Two years later, it became apparent that the couple could not produce a child. They tried various kinds of medicine, but nothing worked. At last, Master Choirom suggested that they talk to a herdsman who had 19 children. They called the herdsman in and he explained his secret: when the horses began to rut, he and his wife would watch them mate, then go mate themselves. Promising to reward the herder if the trick worked, Ujung Aldar Khan agreed to try it.

The couple secretly stole out to the steppe and hid behind a large rock so that they could watch a stallion and mare mate. Afterwards, they returned to their palace and tried for a child. The trick worked, and several months later it became apparent that Urmaa was pregnant. Ujung Aldar Khan sent the herdsman 100 cows as a reward. Urmaa was pregnant for 10 months, but could not give birth. When she finally did give birth, it was to a strange red mass. Ujung Aldar ordered a servant to throw it out, but then a voice cried from within, "I'm suffocating! Let me out of here!" They tried to cut the red mass open with a sword, but the sword merely chipped. Master Choirom came and recommended that they use Sword given by the Jade Emperor, and with this sword they were able to cut the red mass and free the large baby boy within. The baby's skin had auspicious markings: a red mole and a birthmark on his buttocks. The child was strong and kicked his leather swaddling cloths to pieces, making Urmaa afraid that her son was ill-fated to cause destruction. She begged Ujung Aldar to let the child die, but he appreciated his son's strength and refused. The tribe celebrated the baby's birth together.

Ujung Aldar became so preoccupied with his new son that he began to neglect the affairs of the tribe, particularly the defenses. A Manggus, or devil, called Goljing had long been an enemy of Bomba. Seeing Ujung Aldar's weakness, he attacked with 10,000 warriors on black horses and easily captured Bomba. Ujung Aldar Khan and his wife and son were besieged in their palace. Seeking to save his son's life, Ujung Aldar put a piece of white jade in his son's mouth, placed him on the horse Aranjagaan, and sent his servant Menhbayar to take the child to safety. He also gave the servant the Aram spear, a weapon that had been passed down for generations. Then Ujang Aldar fought the invaders until he and his wife were cut down.

The servant took the child to Big Black Mountain and hid him in a cave, then walked back to the palace to see what had happened. Discovering everything destroyed and the Khan dead, he decided to take his revenge by attacking some of the invaders as they sat around a fire. He killed one of them, but was soon killed himself. In the mountain cave, the boy sucked the white jade to keep himself from growing hungry or thirsty for a few days. But eventually he began to cry. A man named Mengen Xigxirge was hunting nearby, and he noticed the horse Aranjagaan grazing. Wanting to see what the horse was doing there, he went closer, and heard the baby crying. He followed the noise and discovered the cave. At first Mengen Xigxirge wanted to adopt the boy, so he decided to give him the name "Jangar." The boy immediately agreed that this should be his name and declared that he would become master of the world. This frightened Mengen Xigxirge, who was worried that Jangar might dispossess his own son, Hongor. So he decided to leave Jangar there with some food and water and left.