Siobhan Trichelle Cropper (born April 13, 1978) is a 2-time Olympian and swimmer from Trinidad and Tobago, who specialized in sprint freestyle and butterfly events. Cropper represented Trinidad and Tobago in two editions of the Olympic Games (1996 and 2000), and eventually captured the 100 m butterfly title at the 1998 Central American and Caribbean Games in Maracaibo, Venezuela. She also holds three Trinidadian records in a sprint freestyle and butterfly double (both 50 and 100 m), two NCAA championship titles and fourteen All-American honors, while attending Stanford University.