William Gay or variants may refer to:

• Willie Gay (baseball) (1909–1970), American baseball player
• Bill Gay (1927–2008), American football defensive back
• William Gay (defensive lineman) (born 1955), retired American NFL player
• William Gay (cornerback) (born 1985), American NFL player drafted by the Pittsburgh Steelers in 2007
• Willie Gay (born 1998), American football linebacker

• William Gay (author) (1941–2012), American writer of novels and short stories
• William Gay (landscape gardener and surveyor) (1814–1893), British landscape gardener and surveyor
• Frank William Gay (1920–2007), also known as Bill Gay, American businessman
• William Gay (poet) (1865–1897), Scottish-born Australian poet

• William G. Brown Sr. (1800–1884), American politician from Virginia and West Virginia
• William Gay Brown Jr. (1856–1916), American politician from West Virginia