Selangor Civil War (1867-73), series of conflicts initially between Malay chiefs but later involving Chinese secret societies for control of tin-rich districts in Selangor.
Following the disputed recognition of Abdul Samad as sultan in 1860, Malay chiefs gradually became polarized into two camps--generally the lower-river versus the upper-river chiefs. The main issue concerned the lucrative collection of duties on tin exports. Raja Mahdi, the dispossessed son of the previous ruler in Klang (now Kelang), seized and held the prosperous town of Klang for two years with tacit approval of dissident upper-river chiefs. When the sultan granted favours to his son-in-law Zia-ud-din, brother of the sultan of Kedah, he further alienated the dissident chiefs, and intermittent fighting commenced.
At this point Chinese tin miners in the Selangor and Klang valleys began feuding over control of the mines. The miners predominantly belonged to the Ghee Hin and Hai San secret societies, which increasingly sought allies among the Malay chiefs. Thus, by 1870 the Chinese had joined opposing sides in the civil war: the Ghee Hin had joined Raja Mahdi's forces, and the Hai San had sided with Zia-ud-din. By late 1873 Zia-ud-din, with British aid, a Pahang army, and his Chinese allies, reversed several years of setbacks and defeated Mahdi and his supporters.
The war caused economic dislocation and loss of mining investments and paved the way for expansion of British control in 1874.