The Warring States period in Chinese history (c. 475 – 221 BC) comprises the final centuries of the Zhou dynasty (c. 1046 – 256 BC), which were characterized by warfare, bureaucratic and military reform, and political consolidation. It followed the Spring and Autumn period and concluded with the wars of conquest that saw the state of Qin annex each of the other contender states by 221 BC and found the Qin dynasty, the first imperial dynastic state in East Asian history.

While scholars have identified several different dates as marking the beginning of the Warring States period, Sima Qian's choice of 475 BC is the most often cited. The era largely corresponds to the second half of the Eastern Zhou period, where the king of Zhou formally ruled as Chinese sovereign, but had lost political power and functioned in practice as a figurehead. This dynamic served as the backdrop for the machinations of the eponymous Warring States. The label "Warring States period" derives from the Record of the Warring States, a work of history compiled during the early Han dynasty (202 BC – 220 AD).

The political geography of the era was dominated by the Seven Warring States, namely:

Besides these seven major states other smaller states survived into the period. They include:

The eastward flight of the Zhou court in 771 BC marks the start of the Spring and Autumn period. No one single incident or starting point inaugurated the Warring States era. The political situation of the period represented a culmination of historical trends of conquest and annexation which also characterised the Spring and Autumn period. As a result, there is some controversy as to the beginning of the era. Proposed starting points include:

The Eastern Zhou dynasty began its fall around 5th century BC. As their influence waned, they had to rely on armies in allied states rather than their own military force. Hundreds of smaller polities coalesced into seven major states which included: Chu, Han, Qin, Wei, Yan, Qi and Zhao. However, there eventually was a shift in alliances because each state's ruler wanted independence. This caused hundreds of wars between 535 and 286 BC. The victorious state would have overall rule and control in China.

The system of feudal states created by the Western Zhou dynasty underwent enormous changes after 771 BC with the flight of the Zhou court to modern-day Luoyang and the diminution of its relevance and power. The Spring and Autumn period led to a few states gaining power at the expense of many others, the latter no longer able to depend on central authority for legitimacy or protection. During the Warring States period, many rulers claimed the Mandate of Heaven to justify their conquest of other states and spread their influence.

The struggle for hegemony eventually created a state system dominated by several large states, such as Jin, Chu, Qin, Yan, and Qi, while the smaller states of the Central Plain tended to be their satellites and tributaries. Other major states also existed, such as Wu and Yue in the southeast. The last decades of the Spring and Autumn era were marked by increased stability, as the result of peace negotiations between Jin and Chu which established their respective spheres of influence. This situation ended with the partition of Jin, whereby the state was divided between the houses of Han, Zhao and Wei, leading to the seven major warring states.