William Gao is an English actor and musician. He is known for his debut role as Tao Xu in the Netflix series Heartstopper which he was nominated for a Children's and Family Emmy Award for Outstanding Supporting Performance.

Gao and his younger sister Olivia Hardy formed a music duo called Wasia Project in 2019.

Gao was born in 2002 or 2003, and he is from South Croydon. He is the son of an English father and a Chinese mother who moved to England in her 20s. He attended the Trinity School, where he completed A Levels in Chinese, music, and drama in 2022. He took up classical piano at the age of 11 and was a member of Trinity Boys Choir. He joined the National Youth Theatre in May 2019.