Fatalism is a belief and philosophical doctrine which considers the entire universe as a deterministic system and stresses the subjugation of all events, actions, and behaviors to fate or destiny, which is commonly associated with the consequent attitude of resignation in the face of future events which are thought to be inevitable and outside of human control.

The term "fatalism" can refer to any of the following ideas:

More specifically:

Throughout history, the belief that the entire universe is a deterministic system subject to the will of fate or destiny has been articulated in both Eastern and Western religions, philosophy, music, and literature.

The ancient Arabs that inhabited the Arabian Peninsula before the advent of Islam used to profess a widespread belief in fatalism (ḳadar) alongside a fearful consideration for the sky and the stars as divine beings, which they held to be ultimately responsible for every phenomenon that occurs on Earth and for the destiny of humankind. Accordingly, they shaped their entire lives in accordance with their interpretations of astral configurations and phenomena.

In the I Ching and philosophical Taoism, the ebb and flow of favorable and unfavorable conditions suggests the path of least resistance is effortless (see: Wu wei). In the philosophical schools of the Indian Subcontinent, the concept of karma deals with similar philosophical issues to the Western concept of determinism. Karma is understood as a spiritual mechanism which causes the eternal cycle of birth, death, and rebirth (saṃsāra). Karma, either positive or negative, accumulates according to an individual's actions throughout their life, and at their death determines the nature of their next life in the cycle of Saṃsāra. Most major religions originating in India hold this belief to some degree, most notably Hinduism, Jainism, Sikhism, and Buddhism.

The views on the interaction of karma and free will are numerous, and diverge from each other greatly. For example, in Sikhism, god's grace, gained through worship, can erase one's karmic debts, a belief which reconciles the principle of karma with a monotheistic god one must freely choose to worship. Jainists believe in a sort of compatibilism, in which the cycle of Saṃsara is a completely mechanistic process, occurring without any divine intervention. The Jains hold an atomic view of reality, in which particles of karma form the fundamental microscopic building material of the universe.

In ancient India, the Ājīvika school of philosophy founded by Makkhali Gosāla (around 500 BCE), otherwise referred to as "Ājīvikism" in Western scholarship, upheld the Niyati ("Fate") doctrine of absolute fatalism or determinism, which negates the existence of free will and karma, and is therefore considered one of the nāstika or "heterodox" schools of Indian philosophy. The oldest descriptions of the Ājīvika fatalists and their founder Gosāla can be found both in the Buddhist and Jaina scriptures of ancient India. The predetermined fate of all sentient beings and the impossibility to achieve liberation (mokṣa) from the eternal cycle of birth, death, and rebirth (saṃsāra) was the major distinctive philosophical and metaphysical doctrine of this heterodox school of Indian philosophy, annoverated among the other Śramaṇa movements that emerged in India during the Second urbanization (600–200 BCE).