The Autonomous Region in Muslim Mindanao (Tagalog: Rehiyong Awtonomo ng Muslim Mindanao; Arabic: الحكم الذاتي الاقليمي لمسلمي مندناو Al-ḥukm adh-dhātī al-'iqlīmī li-muslimī Mindanāu; abbreviated as ARMM) was an autonomous region of the Philippines, located in the Mindanao island group of the Philippines, that consisted of five predominantly Muslim provinces: Basilan (except Isabela City), Lanao del Sur, Maguindanao, Sulu, and Tawi-Tawi. It was the only region that had its own government. The region's de facto seat of government was Cotabato City, although this self-governing city was outside its jurisdiction.

The ARMM included the province of Shariff Kabunsuan from its creation in 2006 until July 16, 2008, when Shariff Kabunsuan ceased to exist as a province after the Supreme Court of the Philippines declared the "Muslim Mindanao Autonomy Act 201", which created it, unconstitutional in Sema v. COMELEC and Dilangalen.

On October 7, 2012, President Benigno Aquino III said that the government aimed to have peace in the autonomous region and that it would become known as the Bangsamoro Autonomous Region, a compound of bangsa (nation) and Moro. On July 26, 2018, Aquino's successor, President Rodrigo Duterte, signed the Bangsamoro Organic Law (BOL), which paved the way for the establishment of a new autonomous political entity in the area, the Bangsamoro Autonomous Region in Muslim Mindanao (BARMM).

ARMM was nominally disestablished after the ratification of BOL and will be effectively replaced by the BARMM upon the constitution of the Bangsamoro Transition Authority, an interim government for the region. The law was "deemed ratified" on January 25, 2019, following the January 21 plebiscite.