Willemien "Minki" (née van der Westhuizen) (born 26 February 1984) is a South African fashion model.
Van der Westhuizen was born in Durbanville, Cape Town, and attended Stellenberg High School in nearby Bellville. She began modelling at age 16, and is currently under the Max Models agency. Van der Westhuizen got her start in international modelling by being selected for a campaign by the fashion label Guess and has been subsequently featured in the 2002, 2003, 2006 and 2007 swimsuit editions of South African Sports Illustrated magazine. She was ranked #24 on the Maxim Hot 100 Women of 2003. She is currently co-hosting Pasella on SABC 2 with former Miss South Africa Cindy Nell.