Guru Purnima is set aside to acknowledge the teacher, whether a spiritual preceptor, an academic mentor or the lineage of sages. Followers visit their guru or the seat of their tradition, offer flowers and cloth, and renew their practice; monastic orders begin the rainy-season retreat, Chaturmasya, on this day. It is also called Vyasa Purnima, honouring Vyasa, who is credited with arranging the Vedas and composing the Mahabharata.
The festival falls on the full-moon day (Purnima) of the month of Ashadha, at the start of the monsoon. As a full-moon observance the puja is generally done during the day while Purnima prevails.
The day is shared across traditions: Buddhists keep it as the anniversary of the Buddha's first sermon at Sarnath, and Jains as the day Mahavira took Gautama Swami as his first disciple. In farming communities of the north it is a pause before the demands of the planting season.