The Acehnese are an indigenous ethnic group from Aceh, Indonesia on the northernmost tip of the island of Sumatra. The area has a history of political struggle against the Dutch colonial rule. The vast majority of the Acehnese people are Muslims. The Acehnese people are also referred to by other names such as Lam Muri, Lambri, Akhir, Achin, Asji, A-tse and Atse. Their language, Acehnese, belongs to the Aceh–Chamic group of Malayo-Polynesian of the Austronesian language family.

Aceh, officially the Province of Aceh, is the westernmost province of Indonesia. It is located on the northern end of Sumatra island, with Banda Aceh being its capital and largest city. It is bordered by the Indian Ocean to the west, Strait of Malacca to the northeast, as well bordering the province of North Sumatra to the east, and shares maritime borders with Malaysia and Thailand to the east, and Andaman and Nicobar Islands of India to the north. Granted a special autonomous status, Aceh is a religiously conservative territory and the only Indonesian province practicing Sharia law officially. There are ten indigenous ethnic groups in this region, the largest being the Acehnese people, accounting for approximately 70% of the region's population of about 5.5 million people in mid-2023. Its area is comparable to Croatia or Togo.