Vaishnavism (Sanskrit: वैष्णव धर्म, Sanskrit pronunciation: [ʋəiˈʂɳəʋə ˈd̪ʱərmə] ; Vaisnava dharma) is one of the major branches of Hinduism along with Shaivism, Smartism, and Shaktism. It is focused on the veneration of Supreme Lord Vishnu. Vaishnavites, or the followers of the Supreme Lord Vishnu, lead a way of life promoting differentiated monotheism (henotheism), which gives importance to Lord Vishnu and his ten incarnations.

The Vedic text, of Rigveda, describes Lord Vishnu as:

om tad visnoh paramam padam sada pasyanti surayah

— diviva caksur atatam

"Just as the sun's rays in the sky are extended to the mundane vision, so in the same way the wise and learned devotees always see the supreme abode of Lord Vishnu."

tad vipraso vipanyavo jagrvam sah samindhate

— visnor yat paramam padam

"Because those highly praiseworthy and spiritually awake devotees are able to see the spiritual world, they are also able to reveal that supreme abode of Lord Vishnu."

In general, the Vaishnava Agamas describe Lord Vishnu as the "supreme being and the foundation of all existence." This is explained in Katha Upanishad 2.2.13: nityo nityanam cetanas cetananam/ eko bahunam yo vidadhati kaman, "the Supreme Being, the Personality of Godhead, is the chief living being amongst all living beings and grants the desires of all other eternal sentient beings"

Its beliefs and practices, especially the concepts of Bhakti and Bhakti Yoga, are based largely on the Upanishads, and associated with the Vedas and Puranic texts such as the Bhagavad Gita, and the Padma, Vishnu and Bhagavata Puranas.

The followers of Vaishnavism are referred to as Vaishnava(s) or Vaishnavites. Awareness, recognition, and growth of the belief has significantly increased outside of India (see: ISKCON) in recent years. The Gaudiya Vaishnava branch of the tradition has significantly increased the awareness of Vaishnavism internationally, since the mid-1900s, largely through the activities and geographical expansion of the Hare Krishna movement founded by A. C. Bhaktivedanta Swami Prabhupada in New York City in 1966, and more recently, through several other Vaishnava organizations such as Pure Bhakti Yoga Society of Srila Bhaktivedanta Narayan Maharaj, conducting preaching activities in the West.