Zhang Yixing (Chinese: 张艺兴; pinyin: Zhāng Yìxīng; born (1991-10-07)October 7, 1991), known professionally as Lay Zhang or simply Lay, is a Chinese rapper, singer-songwriter, dancer, actor, record producer and businessman. Zhang first gained recognition in 2005 for participating in the Chinese television talent show Star Academy. He later debuted as a member of the South Korean-Chinese boy band Exo and its Chinese sub-unit Exo-M under SM Entertainment in 2012.

In 2015, Zhang founded a personal agency with SM for managing his solo activities in China and wrote an autobiography titled Standing Firm at 24. In 2016, Zhang released his first extended play (EP), Lose Control. The EP peaked at number one on the Gaon Album Chart and number four on Billboard's US World Albums chart. Zhang is the first Chinese solo artist to hit the Top 25 on the Billboard 200 and the first Chinese solo artist to hit Top 5 on the Worldwide iTunes Album Chart. Since his debut as a solo artist, Zhang has produced and released over 100 songs including 4 studio albums and 5 EPs, and has won numerous music awards.

In 2020, Zhang founded the Chromosome Entertainment Group and serves as CEO and producer. Zhang has been included on the Forbes China Celebrity 100 (placing in the top 20 in multiple years) and on the CelebrityZ Top 100 Most Valuable Celebrities list (placing 23rd in 2016) published by market research company Kantar and Chinese business magazine CBN Weekly. Outside of music, Zhang became the first celebrity to serve as publicity ambassador for the Communist Youth League of China of Changsha in 2016.

He has also ventured into acting and starred in films and television shows such as Ex-Files 2 (2015), The Mystic Nine (2016), Kung Fu Yoga (2017), The Island (2018), The Golden Eyes (2019), Empress of the Ming (2019), Crime Crackdown (2021), and No More Bets (2023).