In Buddhism, a bodhisattva is a person who has attained, or is striving towards, bodhi ('awakening', 'enlightenment') or Buddhahood. Often, the term specifically refers to a person who forgoes or delays personal nirvana or bodhi in order to compassionately help other individuals reach Buddhahood.

In the Early Buddhist schools, as well as modern Theravāda Buddhism, bodhisattva (or bodhisatta) refers to someone who has made a resolution to become a Buddha and has also received a confirmation or prediction from a living Buddha that this will come to pass. In Theravāda Buddhism, the bodhisattva is mainly seen as an exceptional and rare individual. Only a few select individuals are ultimately able to become bodhisattvas, such as Maitreya.

In Mahāyāna Buddhism, a bodhisattva refers to anyone who has generated bodhicitta, a spontaneous wish and compassionate mind to attain Buddhahood for the benefit of all sentient beings. Mahayana bodhisattvas are spiritually heroic persons that work to attain awakening and are driven by a great compassion (mahākaruṇā). These beings are exemplified by important spiritual qualities such as the "four divine abodes" (brahmavihāras) of loving-kindness (maitrī), compassion (karuṇā), empathetic joy (muditā) and equanimity (upekṣā), as well as the various bodhisattva "perfections" (pāramitās) which include prajñāpāramitā ("transcendent knowledge" or "perfection of wisdom") and skillful means (upāya).

Mahāyāna Buddhism generally understands the bodhisattva path as being open to everyone, and Mahāyāna Buddhists encourage all individuals to become bodhisattvas. Spiritually advanced bodhisattvas such as Avalokiteshvara, Maitreya, and Manjushri are also widely venerated across the Mahāyāna Buddhist world and are believed to possess great magical power, which they employ to help all living beings.

Bodhisattva is a combination of two Sanskrit words: Bodhi (बोधि), meaning "awakening" or "enlightenment" and Sattva (सत्त्व), meaning "being", as pertaining to a person who has achieved, or is striving towards, bodhi ('awakening' or 'enlightenment') or Buddhahood.

In pre-sectarian Buddhism, the term bodhisatta is used in the early texts to refer to Gautama Buddha in his previous lives and as a young man in his last life, when he was working towards liberation. In the early Buddhist discourses, the Buddha regularly uses the phrase "when I was an unawakened Bodhisatta" to describe his experiences before his attainment of awakening. The early texts which discuss the period before the Buddha's awakening mainly focus on his spiritual development. According to Bhikkhu Analayo, most of these passages focus on three main themes: "the bodhisattva's overcoming of unwholesome states of mind, his development of mental tranquillity, and the growth of his insight."

Other early sources like the Acchariyabbhutadhamma-sutta (MN 123, and its Chinese parallel in Madhyama-āgama 32) discuss the marvelous qualities of the bodhisattva Gautama in his previous life in Tuṣita heaven. The Pali text focuses on how the bodhisattva was endowed with mindfulness and clear comprehension while living in Tuṣita, while the Chinese source states that his lifespan, appearance, and glory was greater than all the devas (gods). These sources also discuss various miracles which accompanied the bodhisattva's conception and birth, most famously, his taking seven steps and proclaiming that this was his last life. The Chinese source (titled Discourse on Marvellous Qualities) also states that while living as a monk under the Buddha Kāśyapa he "made his initial vow to [realize] Buddhahood [while] practicing the holy life."

Another early source that discusses the qualities of bodhisattvas is the Mahāpadāna sutta. This text discusses bodhisattva qualities in the context of six previous Buddhas who lived long ago, such as Buddha Vipaśyī. Yet another important element of the bodhisattva doctrine, the prediction of someone's future Buddhahood, is found in another Chinese early Buddhist text, the Discourse on an Explanation about the Past (MĀ 66). In this discourse, a monk named Maitreya aspires to become a Buddha in the future and the Buddha then predicts that Maitreya will become a Buddha in the future Other discourses found in the Ekottarika-āgama present the "bodhisattva Maitreya" as an example figure (EĀ 20.6 and EĀ 42.6) and one sutra in this collection also discuss how the Buddha taught the bodhisattva path of the six perfections to Maitreya (EĀ 27.5).