Merchants and traders played a vital role in transforming Penang into an important port and trading centre after the English East India Company's Francis Light took over the island in 1786. While some studies have highlighted their activities since the formal occupation of Penang, the role and contributions of Muslim merchants have received little attention. In the early years of Penang's economic development this group monopolized the ocean trades, but some writers have seen the large influx of Chinese immigrants in the mid-nineteenth century as overshadowing their role. While this may be true in the Chinese concentration on large-scale trades, Muslim businesses flourished in George Town right through the twentieth century and their activities also extended to Penang's outlying areas and to other communities. This essay looks at their roles, contributions and social impact from the 1860s until the 1970s.