Eschatology (/ˌɛskəˈtɒlədʒi/ ^ⓘ; from Ancient Greek ἔσχατος (éskhatos) 'last' and -logy) concerns expectations of the end of present age, human history, or the world itself. The end of the world or end times is predicted by several world religions (both Abrahamic and Dharmic), which teach that negative world events will reach a climax. Belief that the end of the world is imminent is known as apocalypticism, and over time has been held both by members of mainstream religions and by doomsday cults. In the context of mysticism, the term refers metaphorically to the end of ordinary reality and to reunion with the divine. Many religions treat eschatology as a future event prophesied in sacred texts or in folklore, while other religions may have concepts of renewal or transformation after significant events.

The Abrahamic religions maintain a linear cosmology, with end-time scenarios containing themes of transformation and redemption. In Judaism, the term "end of days" makes reference to the Messianic Age and includes an in-gathering of the exiled Jewish diaspora, the coming of the Messiah, the resurrection of the righteous, and the world to come. Christianity depicts the end time as a period of tribulation that precedes the second coming of Christ, who will face the rise of the Antichrist along with his power structure and false prophets, and usher in the Kingdom of God. The explicit description of a new earth is primarily found in Christian teachings (this description can be found in Chapter 21 of the Book of Revelation). In later traditions of Islam, separate hadiths detail the Day of Judgment as preceded by the appearance of the Masīḥ ad-Dajjāl, and followed by the descending of ʿĪsā (Jesus), which shall triumph over the false Messiah or Antichrist; his defeat will lead to a sequence of events that will end with the sun rising from the west and the beginning of the Qiyāmah (Judgment Day).

Dharmic religions tend to have more cyclical worldviews, with end-time eschatologies characterized by decay, redemption, and rebirth (though some believe transitions between cycles are relatively uneventful). In Hinduism, the end time occurs when Kalki, the final incarnation of Vishnu, descends atop a white horse and brings an end to the current Kali Yuga, completing a cycle that starts again with the regeneration of the world. In Buddhism, the Buddha predicted his teachings would be forgotten after 5,000 years, followed by turmoil. It says a bodhisattva named Maitreya will appear and rediscover the teachings of the Buddha Dharma, and that the ultimate destruction of the world will then come through seven suns.

Since the development of the concept of deep time in the 18th century and the calculation of the estimated age of planet Earth, scientific discourse about end times has considered the ultimate fate of the universe. Theories have included the Big Rip, Big Crunch, Big Bounce, and Big Freeze (heat death). Social and scientific commentators also worry about global catastrophic risks and scenarios that could result in human extinction.

The word "eschatology" arises from the Ancient Greek term ἔσχατος (éschatos), meaning "last", and -logy, meaning "the study of", and first appeared in English around 1844. The Oxford English Dictionary defines eschatology as "the part of theology concerned with death, judgment, and the final destiny of the soul and of humankind".

The main tenets of modern Jewish eschatology, in no particular order, include:

Judaism usually refers to the end times as the "end of days" (aḥarit ha-yamim, אחרית הימים), a phrase that appears several times in the Tanakh. The end times are addressed in the Book of Daniel and in numerous other prophetic passages in the Hebrew scriptures, and also in the Talmud, particularly Tractate Avodah Zarah.

The idea of a Messianic Age, an era of global peace and knowledge of the Creator, has a prominent place in Jewish thought, and is incorporated as part of the end of days. A well-known passage from the Book of Isaiah describes this future condition of the world: "They shall beat their swords into plowshares and their spears into pruning hooks; nation will not lift sword against nation and they will no longer study warfare" (Isaiah 2:4, see also Micah 4:3). Maimonides (1135–1204) further describes the Messianic Era in the Mishneh Torah: "And at that time there will be no hunger or war, no jealousy or rivalry. For the good will be plentiful, and all delicacies available as dust. The entire occupation of the world will be only to know God; ... the people Israel will be of great wisdom; they will perceive the esoteric truths and comprehend their Creator's wisdom as is the capacity of man. As it is written (Isaiah 11:9): 'For the earth shall be filled with the knowledge of God, as the waters cover the sea.'"