Guru Nanak Jayanti, also known as Guru Nanak Gurpurab, is one of the most significant and auspicious festivals in Sikhism. It commemorates the birth anniversary of Guru Nanak Dev Ji, the founder of Sikhism and the first of the ten Sikh Gurus. Guru Nanak Jayanti usually falls on the Kartik Purnima, which is the full moon day in the month of Kartik in the Hindu lunar calendar. This date typically falls in October or November in the Gregorian calendar.