The siege of Kiev by the Mongols took place between 28 November and 6 December 1240, and resulted in a Mongol victory. It was a heavy morale and military blow to the Principality of Galicia–Volhynia, which was forced to submit to Mongol suzerainty, and allowed Batu Khan to proceed westward into Central Europe.

Batu Khan and the Mongols began their invasion in late 1237 by conquering the northeastern Rus' Principality of Ryazan. Then, in 1238 the Mongols went south-west and destroyed the cities of Vladimir and Kozelsk. In 1239, they captured both Pereyaslav and Chernigov with their sights set on Kiev.

The Mongol envoys sent to Kiev to demand submission were executed by Grand Prince Michael of Chernigov. The Mongol capture of Chernigov caused Michael to flee to Hungary in 1239 or 1240. The Smolensk prince Rostislav II Mstislavich seized the opportunity to claim Kiev for himself, but was in turn soon driven out by Daniel of Galicia-Volhynia (Danylo Romanovych).

The next year, Batu Khan's army under the tactical command of the great Mongol general Subutai reached Kiev (in November 1240). At the time, the city was ruled by the Principality of Galicia–Volhynia (Halych-Volhynia, also known as Ruthenia), having been recently captured by Danylo Romanovych. The chief commander in Kiev was Voivode Dmytro, while Danylo was in Hungary at that time, seeking a military union to prevent invasion.^{[citation needed]}

The vanguard army under Batu's cousin Möngke came near the city. Möngke was apparently taken by the splendor of Kiev and offered the city terms for surrender, but his envoys were killed. The Mongols chose to assault the city. Batu Khan destroyed the forces of the Rus vassals, the Chorni Klobuky, who were on their way to relieve Kiev, and the entire Mongol army camped outside the city gates, joining Möngke's troops.^{[citation needed]}

Scholar Alexander Maiorov (2016) compared all the dates in the surviving records of the events, concluding that the siege of Kiev lasted just nine days, from 28 November to 6 December 1240. On 28 November, the Mongols set up catapults near one of the three gates of old Kiev where tree cover extended almost to the city walls. The Mongols then began a bombardment that lasted several days. On 6 December, Kiev's walls were breached, and hand-to-hand combat followed in the streets. The Kievans suffered heavy losses and Dmytro was wounded by an arrow.

When night fell, the Mongols held their positions while the Kievans retreated to the central parts of the city. Many people crowded into the Church of the Tithes. The next day, as the Mongols commenced the final assault, the church's balcony collapsed under the weight of the people standing on it, crushing many. After the Mongols won the battle, they plundered Kiev. Most of the population was massacred. Out of 50,000 inhabitants before the invasion, about 2,000 survived. Most of the city was burned and only six out of forty major buildings remained standing. Dmytro, however, was shown mercy for his bravery.

After their victory at Kiev, the Mongols forced both Galicia and Volhynia to submit to Batu Khan's suzerainty, and they were free to advance westward into Hungary and Poland. The Mongol advance westward only halted in September 1242, when Batu Khan heard the news that Ögedei Khan had died, and Batu needed to attend the quriltai where a successor would be chosen. Soon after, the new Mongol regime began collecting tributes through a Darughachi in Kiev and elsewhere, as Fra Giovanni da Pian del Carpine already observed in the 1240s.