Xu Yanwei (simplified Chinese: 徐妍玮; traditional Chinese: 徐妍瑋; pinyin: Xú Yánwěi; born 14 June 2003 in Shanghai) is an Olympic medal-winning swimmer from the Republic of China (Taiwan), who became part of the Taiwanese national swimming team in 2003.

She was part of Taiwan's 4 × 200 m freestyle relay team, which won the silver medal, beaten by the USA team.

She was also part of Taiwan's 4 × 100 m women's freestyle relay team.

Taiwan reached the final in this event but did not win a medal.

Xu competed as an individual in the 100 m freestyle and 100 m butterfly events, but did not progress past the heat stage in either.