The Inter-Religious Organisation (IRO) had its beginnings as the Inter-Religious Organisation of Singapore and Johor Bahru which was officially launched on 18 March 1949. It was renamed the Inter-Religious Organisation of Singapore in 1961.
When Maulana Abdul Aleem Siddiqui, a well known Muslim missionary, visited Singapore in 1949, an inter-faith reception for him sparked the idea for an inter-faith organisation. Sir Malcolm Macdonald, then the British Commissioner General for Southeast Asia, helped to propel this vision into reality.
The public launch of the Inter-Religious Organisation of Singapore and Johor Bahru, which was held in the Victoria Memorial Hall on 18 March 1949, saw a crowd of 2,000 believers from various religions. The first President of IRO was Reverend Dr. H. B. Amstutz. The IRO Council is made up of 29 members who are constituent members of nine religions. These religions are Hinduism, Judaism, the Zoroastrian faith, Buddhism, Taoism Christianity, Islam, Sikhism and the Baha’i Faith.
In 1961, the organisation was renamed the Inter-Religious Organisation in Singapore. In 2001, the IRO launched its website profiling selected religions. Its publication Religions in Singapore has become a standard text for a summary description of the faith of its members.