Cheng Wan-jung (born 22 February 1988) is a Taiwanese swimmer. At the 2004 Olympics, she competed in the 100 and 200 m butterfly, finishing in 34th and 25th place respectively. At the 2012 Summer Olympics, she competed in the Women's 200 metre butterfly, finishing in 28th place overall in the heats, failing to qualify for the semifinals. She also competed in the 200 m individual medley finishing in 31st place.