Naraka (Sanskrit: नरक; Chinese: 地獄／奈落; pinyin: Dìyù/Nàiluò; Japanese: 地獄／奈落, romanized: Jigoku/Naraku) is a term in Buddhist cosmology usually referred to in English as "hell" (or "hell realm") or "purgatory". Another term used for the concept of hell in earlier writings is niraya. In Cambodia, Naraka was part of Buddhist cosmology and indeed also a Khmer word (នរក; norok) for hell. The Narakas of Buddhism are closely related to Diyu, the hell in Chinese mythology. A naraka differs from the concept of hell in Christianity in two respects: firstly, beings are not sent to Naraka as the result of a divine judgment or punishment; secondly, the length of a being's stay in a naraka is not eternal, though it is usually incomprehensibly long.

A being is born into naraka as a direct result of its accumulated actions (karma) and resides there for a finite period of time until that karma has achieved its full result. After its karma is used up, it will be reborn in one of the higher worlds as the result of karma that had not yet ripened.

The eight hot naraka appear in Jātaka texts and form the basis of the hell system in Mahayana Buddhism. According to them, the hells are located deep under the southern continent of Jambudvīpa, denoting India. They are built one upon the other like stories, the principle being that the more severe kind of damnation is located under the previous one. There are differences in the conception of the naraka's height, breadth, length, depth, and distance, meaning that there is not a clear canonic system of naraka at this point of time besides their size.

Dating the idea of hell within Buddhist tradition proves to be difficult, since ideas were orally transmitted until about 100 BCE when the Pali canon was written down in Ceylon.

However, the concept of hell played a significant role since the early stage of Buddhism, since it is closely connected to the concept of karma. Karma determines into which realm a soul is born. Good actions cause someone to be reborn in heaven or as a human on earth. Bad actions cause one to be reborn in "bad states" (duggati) like animals, hungry ghosts, and as a hell resident. There is barely dharma within these existences and a rebirth in a higher realm is very difficult.

In the Kathāvatthu, one of the earliest Buddhist writings written around 250—100 BCE, a version of hell is fully developed, described, and discussed. It is probably one of the earliest religious works offering a presentation of hell imagery. It discusses related topics such as whether hell is the result of particular bad actions or the committed bad actions themselves. It further is argues that hell is a state experienced in another life as the result of a bad action, connecting hell to the concept of the retribution for bad actions and compensation for good actions.

The historical Buddha rejected the reliance upon deities in order to encourage individuals to take responsibility for their own morality. He and other buddhists encouraged this, especially in the laity that demanded a tangible goal, with the comprehensible symbolism of hell. Just as hell served as a symbol, heaven did as well and acted as a temporary imagining that one could progress beyond and achieve enlightenment. In contrast hell was utilised as a deterrent to actions that would create an opposition to enlightenment.

If the understanding of these dates is correct then the idea of Buddhist hell is prior to the ones in Mediterranean cultures, however, both communicated with one another over the sea and land.