Penpak Sirikul (<small>; RTGS:</small> Phenphak Sirikun), nickname Tai (), is an actress and model, well known in the 1970s and 1980s as a Thai sex symbol. By the age of fifty, she was called the 2,000-Year Woman (), as she was considered "forever young".
Born in Chiang Mai, her real name is Wanphen Khuenkaeo. After winning a beauty contest when she was 19, Penpak became a swimsuit model.
Penpak's first film in 1980 was Dok Sanoh Ban Chao (The sanoh flower blooms in the morning), a drama directed by Jazz Siam. That same year she starred opposite Sorapong Chatree in Fai Narok Khum Lokan (Hell fire).
She had a son at age 30 in February 2012.