Sultan Hussein Mua'zzam Shah ibni Mahmud Shah Alam (1776 – 5 September 1835) was the 18th ruler of Johor-Riau. He signed two treaties with Britain which culminated in the founding of modern Singapore; during which he was nominally given recognition by the British as the Sultan of Johor and Singapore in 1819 and the Sultan of Johor in 1824.