Udasis, also spelt as Udasins, also known as Nanak Putras, are a religious sect of ascetic sadhus centred in northern India who follow a tradition known as Udasipanth. Becoming custodians of Sikh shrines in the 18th century, they were notable interpreters and spreaders of the Sikh philosophy during that time. However, their religious practices border on a syncretism of Sikhism and Hinduism, and they did not conform to the Khalsa standards as ordained by Guru Gobind Singh. When the Lahore Singh Sabha reformers, dominated by Tat Khalsa Sikhs, would hold them responsible for indulging in ritual practices antithetical to Sikhism, as well as personal vices and corruption, the Udasi mahants were expelled from the Sikh shrines.

Sikh sects, denominations, traditions, movements, sub-traditions, also known as sampardai in the Punjabi language, are sub-traditions within Sikhism that believe in different approaches to practicing the religion. All sampradas believe in the One Creator God typically rejecting both idol worship and caste systems. Different interpretations have emerged over time, some of which have a living teacher as the leader. The major historic traditions in Sikhism, states Harjot Oberoi, have included Udasi, Nirmala, Nanakpanthi, Khalsa, Sahajdhari, Namdhari Kuka, Nirankari and Sarvaria.