Ganesha (Sanskrit: गणेश; IAST: Gaṇeśa;  listen (help·info)), also spelled Ganesa and Ganesh, also known as Pillaiyar, Ganapati and Vinayaka, is one of the best-known and most widely worshipped deities in the Hindu pantheon. His image is found throughout India and Nepal. Hindu sects worship him regardless of affiliations. Devotion to Ganesha is widely diffused and extends to Jains, Buddhists, and beyond India.

Although he is known by many other attributes, Ganesha's elephant head makes him particularly easy to identify. Ganesha is widely revered as the Remover of Obstacles and more generally as the Lord of Beginnings and the Lord of Obstacles, patron of arts and sciences, and the deva of intellect and wisdom. He is honoured at the beginning of rituals and ceremonies and invoked as the Patron of Letters during writing sessions. Several texts relate mythological anecdotes associated with his birth and exploits and explain his distinct iconography.

Ganesha emerged as a distinct deity in a clearly recognizable form in the 4th and 5th centuries CE, during the Gupta Period, although he inherited traits from Vedic and pre-Vedic precursors. His popularity rose quickly, and he was formally included among the five primary deities of Smartism (a Hindu denomination) in the 9th century. A sect of devotees called the Ganapatya (Sanskrit: गाणपत्य; IAST: gāṇapatya), who identified Ganesha as the supreme deity, arose during this period. The principal scriptures dedicated to Ganesha are the Ganesha Purana, the Mudgala Purana, and the Ganapati Atharvashirsa.