The Council of Indonesian Muslim Associations (Partai Majelis Syuro Muslimin Indonesia), better known as the Masyumi Party, was a major Islamic political party in Indonesia during the Liberal Democracy Era in Indonesia. It was banned in 1960 by President Sukarno for supporting the PRRI rebellion.
In 1909, a trade organization called the Islamic Trading Association (Sarekat Dagang Islam) was established in Java, then part of the Dutch East Indies, to protect the interests of batik traders in the face of competition from ethnic Chinese merchants. In 1912, this became the Sarekat Islam (Islamic Union), and was headed by western-educated Oemar Said Tjokroaminoto.
Although it began as a non-political organization, it began to speak out against injustice and poverty. By 1918, it had 450,000 members. Communist influence within it grew, but so did that of the reformist Islamic Muhammadiyah organization, which was anti-communist. In 1920, Muhammadiyah merged into Sarkat Islam. In 1923, Tjokroaminoto moved to expel communists from the organization at the SI Congress, and established the Islamic Union Party (Partai Sarekat Islam - PSI), which adopted a policy of non-collaboration with the Dutch.
In 1929 the party was renamed the Indonesian Islamic Union Party (PSII). The next few years saw splits within the party, worsened by the death of Tjokroaminoto in 1937. In September 1937, Muhammadiyah and the traditionalist Nahdlatul Ulama established the Supreme Islamic Council of Indonesia (MIAI), an umbrella group for Islamic organizations. Following their 1942 invasion of the Dutch East Indies, the Japanese authorities banned the PSII, but allowed the MIAI to continue. However, it became dominated by former PSII members, so it in turn was dissolved in 1943.
In November the Japanese established an organization called the Council of Indonesian Muslim Associations (Masyumi) in an attempt to control Islam in Indonesia. It too included Muhammadiyah and the Nahdlatul Ulama.