Sanchai Ratiwatana (Thai: สรรค์ชัย รติวัฒน์, pronounced [sǎn.t͡ɕʰāj rá(ʔ).tī.wát]), nicknamed Tong (ต้อง, [tɔ̂ŋ]; born 23 January 1982), is a professional tennis player from Thailand.

He turned professional in 2004.

In 2007, Sanchai and his twin brother Sonchat Ratiwatana won their first ATP doubles title in Bangkok.

They won their second title at the Chennai Open in India in 2008.

39, his best doubles ranking, on 28 April 2008.