Oey was born into an old family of the 'Cabang Atas' aristocracy in the Dutch East Indies (modern-day Indonesia). His father, Oey Khe Tay, also served as Kapitein der Chinezen of Tangerang from 1884 until dying in office in 1897, while his great-grandfather, Oey Eng Sioe, was a der Chinezen from 1856 until 1864 before retiring with the honorary rank of Kapitein-titulair der Chinezen. Oey's mother, Nie Kim Nio, was the daughter of Nie Boen Tjeng, Kapitein der Chinezen and a descendant of Kapitein Nie Hoe Kong, who was in office at the time of the Chinese Massacre of Batavia in 1740. As a descendant of Chinese officers, Oey bore the title 'Sia' from birth. In addition to their tradition of public service, his family also owned extensive "particuliere landerijen", or private domains, in Tangerang, centred on Karawatji.