Indonesian-Malaysian orthography reform of 1972

The Indonesian-Malaysian orthography reform of 1972 was a joint effort between Indonesia and Malaysia to harmonize the spelling system used in their national languages, which are both forms of the Malay language. For the most part, the changes made in the reform are still used today. This system uses the Latin alphabet and in Malaysia is called Joint Rumi Spelling (Malay: Ejaan Rumi Bersama, ERB), and in Indonesia Perfect Spelling or Enhanced Spelling (Indonesian: Ejaan yang Disempurnakan, EYD). It replaced the Za'aba Spelling that was previously standard in Malaysia, Singapore and Brunei, and the Republican Spelling System in Indonesia.

Historically, Indonesia and Malaysia—the two largest Malay-speaking countries, in that order—were divided between two colonial administrations, under the Dutch and British empires respectively. Thus, the development of spelling systems for Rumi script were greatly influenced by the orthographies of their respective colonial tongues. Shortly after the end of Indonesia-Malaysia confrontation in 1966, a common spelling system became among the first items on the agenda of a detente between the two countries.

The new spelling system, known as 'New Rumi Spelling' in Malaysia and 'Perfected Spelling System' in Indonesia, was officially announced in both countries on 16 August 1972. Although the representations of speech sounds are now largely identical in the Indonesian and Malaysian varieties, a number of minor spelling differences remain.