Gamelan () (Javanese: ꦒꦩꦼꦭꦤ꧀, Sundanese: ᮌᮙᮨᮜᮔ᮪, Balinese: ᬕᬫᭂᬮᬦ᭄) is the traditional ensemble music of the Javanese, Sundanese, and Balinese peoples of Indonesia, made up predominantly of percussive instruments. The most common instruments used are metallophones (played with mallets) and a set of hand-drums called kendang, which keep the beat. The kemanak, a banana-shaped idiophone, and the gangsa, another metallophone, are also commonly used gamelan instruments on Bali. Other notable instruments include xylophones, bamboo flutes (similar to the Indian bansuri), a bowed string instrument called a rebab (somewhat similar to the gadulka of Bulgaria), and a zither-like instrument called a siter, used in Javanese gamelan. Additionally, vocalists may be featured, being referred to as sindhen for females or gerong for males.

Although the popularity of gamelan has declined slightly since the introduction of modern popular music to Indonesia, the art form is still widely respected, being commonly played in many traditional ceremonies. It may also be performed as entertainment for some modern events, such as official cultural, corporate, government or educational functions, both formal or informal. Gamelan is also, traditionally, arranged and performed to accompany religious rituals, ceremonies, dance theatre, dance-drama, traditional Indonesian theater, wayang puppets theatre, singing, concerts, festivals, exhibitions, and many more. Many consider gamelan to be an integral part of Indonesian culture.

In 2014, Gamelan traditions were recognized as part of the National Intangible Cultural Heritage of Indonesia by the Indonesian Ministry of Education and Culture.

On 15 December 2021, Gamelan was inscribed onto the UNESCO Representative List of the Intangible Cultural Heritage of Humanity. The nomination builds on the archaeological connection to the Borobudur, and includes a focus on its role in fostering a sense of national identity and pride, in addition to wellbeing aspects such as mental health, the development of interpersonal skills and the connection between its cosmology and an ethics of mutual respect and care. The listing consists of Javanese gamelan (gamelan jawa) of Central Java and Special Region of Yogyakarta, Balinese gamelan (gamelan bali) of Bali, Sundanese gamelan (gamelan sunda) of West Java, Madurese gamelan (gamelan madura) and Banyuwangian Gamelan (gamelan banyuwangi) of East Java, Gendang beleq of West Nusa Tenggara, Banjarese gamelan (gamelan banjar) of South Kalimantan, Gamelan peking of Lampung, and Talempong of West Sumatra as a Masterpiece of Oral and Intangible Heritage of Humanity from Indonesia, and encouraged the Indonesian people and the Indonesian government to safeguard, transmit, promote, and develop the gamelan. Methods include the support of national, international and provincial festivals, the establishment of educational curricula including the Gamelan Goes to School program, an intention to increase the numbers of regional gamelan associations, and cultural diplomacy by sending gamelan specialists to global universities.