Khouw Oen Giok Sia (1874 – 1927), later more popularly known as Oen Giok Khouw or O. G. Khouw, was a prominent philanthropist and landowner in the Dutch East Indies (now Indonesia). He gained notoriety for acquiring Dutch citizenship, thus breaking down the race barriers of colonial society. Today, he is best remembered for his extravagant mausoleum in Petamburan, Jakarta. Together with Mas Asmioen and Oey Tiang Hok, he shocked Dutch colonial society by becoming naturalized citizens of the Netherlands in 1908. In so doing, they bypassed the racial caste system of colonial Indonesia.