Maitreya (Sanskrit: मैत्रेय) or Metteyya (Pali: मेत्तेय्य), also Maitreya Buddha or Metteyya Buddha , is regarded as the future Buddha of this world in Buddhist eschatology. As the fifth and final Buddha of the current kalpa, Maitreya's teachings will be focused around re-establishing the dharma, a vital concept in Hinduism, Buddhism, and Jainism.

In all branches of Buddhism, Maitreya Buddha is viewed as the direct successor of Gautama Buddha. (In some Buddhist literature, such as the Amitabha Sutra and the Lotus Sutra , he is referred to as Ajita). According to scriptures, Maitreya's teachings will be similar to those of Gautama Buddha (also known as Śākyamuni Buddha). The arrival of Maitreya is prophesied to occur during an era when the teachings of Gautama Buddha have been disregarded or largely forgotten.

Despite many religious figures and spiritual leaders claiming to be Maitreya throughout history, diverse Buddhist sects insist that these are false claims, while underscoring that Maitreya has yet to appear, and that he is the Buddha of the future. While Maitreya is said to be a bodhisattva who has long been prophesied to appear on Earth (being mentioned in scriptures as early as the 3rd century CE), traditional Buddhists belief that Maitreya at present resides in Tushita heaven. On account of his enlightenment and his relinquishing any sense of personal self or ego, Maitreya is poised to teach self-realization, as well as right action and right relationship, or the Dharma.

Maitreya has also been employed in a millenarian role by many non-Buddhist philosophies and religions, such as Theosophy, the White Lotus, as well as by modern new religious movements, such as Yiguandao.