The mosque was built by and named after an Arab merchant from Hadhramaut (a valley on eastern Yemen) Syed Omar bin Ali Aljunied (1792 – 1852). After Sir Stamford Raffles founded Singapore in 1819, he invited Syed Omar and his uncle Syed Mohamad, who was a successful businessman in Palembang, Sumatra to set up their business in Singapore. After arriving in Singapore, the Aljunieds became major landowners and philanthropists and shared much of their wealth with the community at large.

The original mosque was established in 1820 at the southern end of Kampong Melaka. The area then became a social hub for the Malay community as well as Muslims originating from India, the Middle East and Southeast Asia.


Islam as a faith spread to the Malay Archipelago from the 13th century and resulted in the building of masjid (Malay for “mosques”) and surau (“prayer halls” in Malay) in towns and villages around the region. Early mosques in Singapore were simple timber structures distinguished by a pyramidal roof with multiple tiers. During the colonial era, brick mosques were built and some of these buildings, incorporated an onion-shaped dome reminiscent of Persian architecture.

As the population grew, the original timber mosque at Kampong Melaka was rebuilt in 1855 by Syed Abdullah bin Omar Aljunied, the son of Syed Sharif Omar. The new building was a sturdier and larger brick hall linked by a paved road to the surrounding neighbourhood. It was built in the Melakan style, with a two-tier pyramidal tiled roof.


This structure remained until the 1980s, when a major reconstruction of the mosque took place. A 28m high minaret with a small roof dome was added to the mosque entrance in 1985. A small street called Omar Road once led to the mosque from Havelock Road, but this road, already named in an 1857 map, was expunged in the 1980s. The Chinese called Omar Road kam kong mak la kah sam pai yang teng hang (“Kampong Melaka praying temple [mosque] lane” in Hokkien). Keng Cheow Street, which survives, was named after Tan Keng Cheow (1907-1972), a Hokkien businessman is now the main entrance of the mosque.