平安时代是日本古代的最后一个历史时代，它从794年桓武天皇将首都从长冈京（784年至794年）移到平安京（现在的京都）开始，到1192年源赖朝创建镰仓幕府一揽大权为止。平安时代的称呼来自其首都的名字。它之前是奈良时代，之后是镰仓时代。

平安时代是日本天皇政府的顶点，也是日本古代文学发展的顶峰。在平安时代中武士阶层得到发展，到这个时代的后期，武士阶层从贵族手中夺取权力，创建幕府。

平安时代日本在804年、838年有两次遣唐使交往（894年未成行）。天台和真言密宗佛教得到发展。

894年废止遣唐使之后，开始发展日本独自的国风文化。

The Heian period(平安时代,Heian jidai) is the last division of classical Japanese history, running from 794 to 1185. The period is named after the capital city of Heian-kyō, or modern Kyōto. It is the period in Japanese history when Buddhism, Taoism and other Chinese influences were at their height. The Heian period is also considered the peak of the Japanese imperial court and noted for its art, especially poetry and literature. Although the Imperial House of Japan had power on the surface, the real power was in the hands of the Fujiwara clan, a powerful aristocratic family who had intermarried with the imperial family. Many emperors actually had mothers from the Fujiwara family. Heian(平安) means "peace" in Japanese.