Sng Ju Wei (born 3 June 1980) is a Singaporean former swimmer, who specialized in sprint and middle-distance freestyle events.

Sng also trained for the Aquatic Performance Swim Club in Singapore district, under head coach Jin Xia Li.

[5] As a member of the Singaporean squad, Sng also placed fifteenth in the 4×200 m freestyle relay (7:54.19), and twenty-third in the 4×100 m medley relay (3:59.51), along with his teammates Desmond Koh, Gerald Koh, and Thum Ping Tjin.

[6][7] At the 2000 Summer Olympics in Sydney, Sng drastically shortened his program, swimming only in the 400 m freestyle on the first day of the Games.

[8] He established a Singaporean record of 4:01.34 to hit the wall first in heat one, holding off Chile's Giancarlo Zolezzi by 0.17 of a second.