The Eastern Zhou^{[lower-alpha 1]} is a period in Chinese history comprising the latter half of the Zhou dynasty from c. 771 BCE to 256 BCE, following the Zhou capital's relocation eastward to Chengzhou, near present-day Luoyang. The Eastern Zhou was characterised by the weakened authority of the Zhou royal house, it is subdivided into two parts: the Spring and Autumn period (c. 771 – c. 481 BCE), during which the ancient aristocracy still held power in a large number of separate polities, and the Warring States period (c. 481 – 221 BCE), which saw the consolidation of territory and escalation of interstate warfare and administrative sophistication.

In 770 BCE, the Zhou capital was moved from Haojing (Chang'an County in Xi'an City) to Chengzhou, near present-day Luoyang.. With the death of King You of Zhou,^[3] the last king of the Western Zhou Dynasty, Crown Prince Yijiu was proclaimed the new king by the nobles from the states of Zheng, Lü, Qin and the Marquess of Shen. He became King Ping of Zhou. In the second year of his reign, he moved the capital east to Luoyi as Quanrong invaded Haojing, spelling the end of the Western Zhou dynasty. The first half of the Eastern Zhou dynasty, from approximately 771 to 476 BCE, was called the Spring and Autumn period, during which more and more dukes and marquesses obtained regional autonomy, defying the king's court in Luoyi, and waging wars amongst themselves. The second half of the Eastern Zhou dynasty, from 475 to 221 BCE, was called the Warring States period,^[3] during which the King of Zhou gradually lost his power and ruled merely as a figurehead.

After moving the capital east, the Zhou royal family fell into a state of decline. Also, King Ping's popularity fell as rumors went that he had killed his father. With vassals becoming increasingly powerful, strengthening their position through defeating other rival states, and increasing invasion from neighboring countries, the king of Zhou was not able to master the country. Constantly, he would have to turn to the powerful vassals for help. The most important vassals (known later as the twelve vassals) came together in regular conferences where they decided important matters, such as military expeditions against foreign groups or against offending nobles.^[4] During these conferences one vassal ruler was sometimes declared hegemon. Chancellor Guan Zhong of Qi initiated a policy "Revere the king, expel the barbarians" (尊王攘夷, see Sonnō jōi). Adopting and adhering to it, Duke Huan of Qi assembled the vassals to strike down the threat of barbarians from the country. During the Warring States period, many of the leading vassals' clamoring for kingship further limited the Zhou royal family's influence.^[5]

In 635 BCE, the Chaos of Prince Dai took place. King Xiang of Zhou turned to Duke Wen of Jin for help, who killed Prince Dai and was rewarded with rule over Henei and Yangfan.^[3] In 632 BCE, King Xiang of Zhou was forced by Duke Wen of Jin to attend the conference of vassals in Jiantu.^[3]

In 606, King Zhuang of Chu inquired for the first time regarding the "weight of the Nine Tripod Cauldrons" only to be rebuffed by the Zhou minister Wangsun Man (王孫滿).^[3] Asking such a question was, at that time, a direct challenge to the power and authority of the reigning dynasty.

At the time of King Nan of Zhou, the kings of Zhou had lost almost all political and military power, as even their remaining crown land was split into two states or factions, led by rival feudal lords: West Zhou, where the capital Wangcheng was located, and East Zhou, centered at Chengzhou and Kung. King Nan of Zhou managed to preserve his weakened dynasty through diplomacy and conspiracies for fifty-nine years until his deposition and death by Qin in 256 BCE. Seven years later, West Zhou was conquered by Qin.^[3]

The dominant material for making tools had become iron by the end of the Eastern Zhou; as such, it is considered to be the beginning of the Iron Age in China. There was a considerable development in agriculture with a consecutive increase in population. There were constantly fights between vassals to scramble for lands or other resources. People started using copper coins. Education was made universal for civilians. The boundaries between the nobility and the civilians subsided. A revolutionary transformation of the society was taking place, to which the patriarchal clan system made by the Zhou Dynasty could no longer adapt.^[6]

• King Ping of Zhou — Ji Yijiu (772–720 BCE)
• King Xie of Zhou — Ji Yuchen (770–760 BCE or 771–750 BCE)
• King Huan of Zhou — Ji Lin (719–697 BCE)
• King Zhuang of Zhou — Ji Tuo (696–682 BCE)
• King Xi of Zhou — Ji Huqi (681–677 BCE)
• King Hui of Zhou — Ji Lang (676–652 BCE)
• King Xiang of Zhou — Ji Zheng (651–619 BCE)
• King Qing of Zhou — Ji Renchen (618–613 BCE)
• King Kuang of Zhou — Ji Ban (612–607 BCE)
• King Ding of Zhou — Ji Yu (606–586 BCE)
• King Jian of Zhou — Ji Yi (585–572 BCE)
• King Ling of Zhou — Ji Xiexin (571–545 BCE)
• King Jing of Zhou — Ji Gui (544–520 BCE)
• King Dao of Zhou — Ji Meng (520 BCE)
• King Jing of Zhou — Ji Gai (519–477 BCE)
• King Yuan of Zhou — Ji Ren (476–469 BCE)
• King Zhending of Zhou — Ji Jie (468–441 BCE)
• King Ai of Zhou — Ji Quji (441 BCE)
• King Si of Zhou — Ji Shu (441 BCE)
• King Kao of Zhou — Ji Wei (440–426 BCE)
• King Weilie of Zhou — Ji Wu (425–402 BCE)
• King An of Zhou — Ji Jiao (401–376 BCE)
• King Lie of Zhou — Ji Xi (375–369 BCE)
• King Xian of Zhou — Ji Bian (368–321 BCE)
• King Shenjing of Zhou — Ji Ding (320–315 BCE)
• King Nan of Zhou — Ji Yan (314–256 BCE)

The period's name derives from the Spring and Autumn Annals, a chronicle of the state of Lu between 722 and 479 BCE, which tradition associates with Confucius.

During this period, the Zhou royal authority over the various feudal states started to decline, as more and more dukes and marquesses obtained de facto regional autonomy, defied the king's court in Luoyi, and waged wars amongst themselves. The gradual partition of Jin, one of the most powerful states, marked the end of the Spring and Autumn period and the beginning of the Warring States period.

The Warring States period was an era in ancient Chinese history following the Spring and Autumn period, concluding with the Qin wars of conquest. Those wars resulted in the annexation of all other contender states, completed with the Qin state's victory in 221 BCE. That meant that the Qin state became the first unified Chinese empire, known as the Qin dynasty.