Tan Siok Tjien is an Indonesian businesswoman has an estimated net worth of $10.2 billion as of April 2019.

Tjien and her family managed the second largest cigarette manufacturer, Gudang Garam in Indonesia. The said company was founded in 1958 by her late husband, Surya Wonowidjojo who died in 1985.

She has five children. In 1983, his eldest son, Rachman Halim became the president director of the company. He died in 2008. The following year, Tjien's daughter, Juni Setiawati hailed as Gudang Garam's president commissioner. Meanwhile, her younger son, Susilo is the current president of the company.