Felix Yanwar Siauw (traditional Chinese: ???; simplified Chinese: ???; pinyin: Xiao Zhèng Guó, born January 31, 1984) is a Chinese-Indonesian Islamic cleric (ustad), preacher, author and da'i, known for his affiliation with the Islamist group Hizbut Tahrir Indonesia (HTI), and his hard-line puritanical position on Islamic interpretations.