Chou Tzu-yu (周子瑜; born June 14, 1999), known mononymously as TZUYU (Hangul: 쯔위), is a Taiwanese singer based in South Korea. She is a member of the girl group TWICE (트와이스), where she debuted on October 20, 2015, with the mini album The Story Begins. She made her solo debut on September 6, 2024, with the mini album abouTZU, making her the third TWICE member to debut as a soloist.