Sanamahism, also known as Meiteism, or Lainingthouism is an ethnic religion of the Meitei people of Manipur, in Northeast India. It is a polytheistic religion and is named after Lainingthou Sanamahi, one of the most important deities of the Meitei faith. Sanamahi is the eldest son of the supreme god Sidaba Mapu and the supreme goddess Leimarel Sidabi. Traditionally every Meitei household, irrespective of the religion, worships Sanamahi and Leimarel Sidabi. Sanamahism does not have a religious head but has a body, the Maru Loishang, that oversees the main religious activities and governs all affairs of the religion, including the conduct of priest and priestess. The Maru Loishang also acts a court for religious disputes. There are three main departments under the Manu Loishang, namely, the Amaiba Loishang, the Pena Asheiba Loishang, and the Amaibi Loishang. These departments have existed since the reign of King Meidingu Hongnemyoi Khunjao Naothingkhong of Manipur in 662 AD. Sanamahi is the eldest son of the supreme god Sidaba Mapu and the supreme goddess Leimarel Sidabi.

The Meitei people, Meetei, Manipuri people is an ethnic group native to Manipur. They form the largest and dominant ethnic group of Manipur in Northeast India. They speak the Meitei language, one of the 22 official languages of the Indian Republic and the sole official language of Government of Manipur. The Meiteis primarily settled in the Imphal Valley region in modern-day Manipur, though a sizeable population has settled in the other Indian states of Assam, Tripura, Nagaland, Meghalaya, and Mizoram. There is also a notable presence of Meitei people in the neighbouring countries of Myanmar and Bangladesh. The Meitei ethnic group represents about 53% of Manipur's population.