The Qin dynasty was the first dynasty of Imperial China, lasting from 221 to 206 BCE. Named for its heartland in Qin state (modern Gansu and Shaanxi), the dynasty was founded by Qin Shi Huang, the First Emperor of Qin. The strength of the Qin state was greatly increased by the Legalist reforms of Shang Yang in the fourth century BCE, during the Warring States period. In the mid and late third century BCE, the Qin state carried out a series of swift conquests, first ending the powerless Zhou dynasty and eventually conquering the other six of the Seven Warring States. Its 15 years was the shortest major dynasty in Chinese history, consisting of only two emperors. Despite its short reign, however, the lessons and strategies of the Qin shaped the Han dynasty and became the starting point of the Chinese imperial system that lasted from 221 BCE, with interruption, development, and adaptation, until 1912 CE.

The Qin sought to create a state unified by structured centralized political power and a large military supported by a stable economy. The central government moved to undercut aristocrats and landowners to gain direct administrative control over the peasantry, who comprised the overwhelming majority of the population and labour force. This allowed ambitious projects involving three hundred thousand peasants and convicts, such as connecting walls along the northern border, eventually developing into the Great Wall of China, and a massive new national road system, as well as the city-sized Mausoleum of the First Qin Emperor guarded by the life-sized Terracotta Army.

The Qin introduced a range of reforms such as standardized currency, weights, measures and a uniform system of writing, which aimed to unify the state and promote commerce. Additionally, its military used the most recent weaponry, transportation and tactics, though the government was heavy-handedly bureaucratic. Han Confucians portrayed the legalistic Qin dynasty as a monolithic tyranny, notably citing a purge known as the burning of books and burying of scholars although some modern scholars dispute the veracity of these accounts.