Mỹ Sơn (Vietnamese pronunciation: [mǐˀ səːn]) is a cluster of abandoned and partially ruined Shaiva Hindu temples in central Vietnam, constructed between the 4th and the 13th century by the Kings of Champa, an Indianized kingdom of the Cham people. The temples are dedicated to the veneration of God in accordance with Shaivism, wherein God is named Shiva, or The Auspicious One. In this particular complex, he is venerated under various local names, the most important of which is Bhadreshvara.

Mỹ Sơn is located near the village of Duy Phú, in the administrative district of Duy Xuyên in Quảng Nam Province in Central Vietnam, 69 km southwest of Da Nang, and approximately 10 km from the historic Champa capital of Trà Kiệu. The temples are in a valley roughly two kilometres wide that is surrounded by two mountain ranges.

From the 4th to the 13th century AD, the valley at Mỹ Sơn was a site of religious ceremony for kings of the ruling dynasties of Champa, as well as a burial place for Cham royalty and national heroes. It was closely associated with the nearby Cham cities of Indrapura (Đồng Dương) and Simhapura (Trà Kiệu). At one time, the site encompassed over 70 temples as well as numerous stele bearing historically important inscriptions in Sanskrit and Cham

Mỹ Sơn is perhaps the longest inhabited archaeological site in Mainland Southeast Asia, but a large majority of its architecture was destroyed by US bombing during a single week of the Vietnam War.

The Mỹ Sơn temple complex is regarded one of the foremost Shaiva Hindu temple complexes in Southeast Asia and is the foremost heritage site of this nature in Vietnam. It is often compared with other historical temple complexes in Southeast Asia, such as Borobudur of Java in Indonesia, Angkor Wat of Cambodia, Wat Phou of Laos, Bagan of Myanmar and Prasat Hin Phimai of Thailand. As of 1999, Mỹ Sơn has been recognized by UNESCO as a World Heritage Site. At its 23rd meeting, UNESCO accorded Mỹ Sơn this recognition pursuant to its criterion C (II), as an example of evolution and change in culture, and pursuant to its criterion C (III), as evidence of an Asian civilization which is now extinct.

In 1937, French scholars began to restore the temples at Mỹ Sơn. In 1937 and 1938, the main temple known as "A1" and the smaller temples surrounding it were restored. Other major temples were restored between 1939 and 1943. However, many historical buildings were destroyed during the Vietnam War. The temples were part of a People's Army of Vietnam and Viet Cong base area and consequently United States aircraft bombed the region in August 1969. The surrounding area is still rendered dangerous through the presence of unexploded land mines.

The majority of the temple sites in the centre of the complex have survived to this day. However, worries persist regarding the structural soundness of the remaining temples, some of which are vulnerable to collapse. Although many statues have been removed to France or to historical museums in Vietnam, such as the Museum of Cham Sculpture in Da Nang, others can be viewed in an in-situ museum that has been set up with the funding of benefactors from Germany and Poland. In 1981, the restoration works were carried out by a team of Polish conservators from Lublin, headed by Kazimierz Kwiatkowski Kazik.

From 2002 to 2004, the Ministry of Culture of Vietnam allotted around US$440,000 to maintain the site. A draft plan of UNESCO was funded by the Government of Italy and sponsors from Japan to prevent further degradation. These efforts are also funded by the World Monuments Fund.

India has supported conservation and restoration of the UNESCO world heritage site of ‘My Son’ in Quang Nam Province of Central Vietnam, which represents historical links between the two countries. Towards the conservation of Cham monuments at My Son, a request was received from Vietnam and as a follow up to this, the ASI Technical Team prepared a Preliminary Observation Report as mandated by the Ministry of External Affairs. Subsequently a Memorandum of Understanding was signed between the Government of India and Government of Vietnam on 28th October 2014. Thereafter, a Technical Team of the ASI conducted survey and prepared detailed estimates and documentation work.

India has extended assistance through the Archaeological Survey of India (ASI) in conservation of three blocks of Cham temples in Central Vietnam’s UNESCO World Heritage Site at My Son in Quang Nam Province, which have been restored by ASI during 2017-22 at an outlay of US$ 2.25 million. The completion of conservation and restoration of A, H and K group of temples by ASI was marked on 20 December 2022 at the My Son complex site in Quang Nam province.