Jessica Evelyn Pengelly (born 1 July 1991 in Edenvale, Gauteng) is a South African swimmer, who specialized in freestyle and individual medley events. She also won the 2013 BHP Billiton Aquatic Super Series Open Water Challenge 2.5 km race in Perth, Australia.
She is a multiple-time South African champion and record holder for the individual medley events (both 200 and 400 m), and a five-time medalist at the 2007 All-Africa Games in Algiers, Algeria. She also set two national records, as a member of the South African swimming team, for the freestyle relay, at the 2008 FINA World Short Course Championships in Manchester, England, and at the 2011 Summer Universiade in Shenzhen, China. At age seventeen, Pengelly became the youngest swimmer to represent South Africa for the 2008 Beijing Olympics where she competed in two individual medley events. Pengelly currently resides in Perth, Western Australia, where she trains for the City of Perth Swimming Club under her head coach Matt Magee.