The Taira clan (平氏, Taira or Hira or Hei-shi^?) was a major Japanese clan of samurai in historical Japan.

In reference to Japanese history, along with Minamoto, Taira was a hereditary clan name bestowed by the emperors of the Heian Period to certain ex-members of the imperial family when they became subjects. The Taira clan is often referred to as Heishi (平氏^?, literally "Taira clan") or Heike (平家^?, literally "House of Taira"), using the character's Chinese reading hei.

Offshoots of the imperial dynasty, some grandsons of Emperor Kammu were first given the name Taira in 825 or later. Afterwards, descendants of Emperor Nimmyō, Emperor Montoku, and Emperor Kōkō were also given the surname. The specific hereditary lines from these emperors are referred to by the emperor's posthumous name followed by Heishi. i.e. Kammu Heishi.

The Taira were one of the four important clans that dominated Japanese politics during the Heian period (794-1185) - the others were the Fujiwara, the Tachibana and the Minamoto.

Taira no Kiyomori (平 清盛^?, 1118 – March 20, 1181) was a military leader of the late Heian period of Japan. He established the first samurai-dominated administrative government in the history of Japan.

After the death of his father Taira no Tadamori in 1153, Kiyomori assumed control of the Taira clan and ambitiously entered the political realm in which he had previously only held a minor post. In 1156, he and Minamoto no Yoshitomo, head of the Minamoto clan, suppressed the Hōgen Rebellion. This established the Taira and Minamoto samurai clans as the top warrior clans in Kyoto. However, their new strength in effect caused the allies to become bitter rivals which culminated three years later during the Heiji Rebellion in 1159. Kiyomori, emerging victorious with Yoshitomo and his two eldest killed, was now the head of the single most powerful warrior family/clan in Kyoto. However, his clan's power and influence in the provinces at this time is a matter of debate. Kiyomori showed mercy and exiled a few of Yoshitomo's sons, including Yoritomo, Noriyori, and Yoshitsune – a benevolence that would turn out to be the Taira clan's downfall later on.

Taira no Masakado (平 将門^?, died in the second lunar month of 940) was a samurai in the Heian period of Japan, who led a rebellion against the central government of Kyoto.

Masakado was born into a prominent noble lineage, the Kammu Heishi Taira of Japan. He served the imperial court in the capital as a youth, and then settled down to the life of a country gentleman in the provinces of eastern Japan, to the northeast of modern day Tokyo.

His career is detailed in Shōmonki (“The Masakado Chronicle”), a literary account of his life believed to have been completed as early as the 940s (although the earliest surviving copy dates from 1099) by an anonymous author.

The Taira Masakado Insurrection of 939-940 (known in Japanese as Jōhei - Tengyo no ran, after the calendar eras in which it occurred) ranks among the most dramatic episodes in the early history of the samurai. Coinciding with earthquakes, rainbows and lunar eclipses in the capital; uprisings in the north; and pirate disturbances in the west; it threw the court and the capital into a panic, and climaxed, according to most versions of the story, with the protagonist’s claiming for himself the title, “New Emperor.” Many historians have perceived the incident as an early harbinger of the late twelfth-, thirteenth- and fourteenth-century events that, step by step, ushered in the medieval era of warrior rule.