William James Gaither (/ˈɡeɪθər/ GAY-thər; born March 28, 1936) is an American singer and songwriter of Southern gospel and contemporary Christian music. He has written numerous popular Christian songs with his wife Gloria; he is also known for performing as part of the Bill Gaither Trio and the Gaither Vocal Band. In the 1990s, his career gained a resurgence (as well as the careers of other southern gospel artists), as popularity grew for the Gaither Homecoming series. In 2023, he released a secular music album with the Gaither Vocal Band entitled Love Songs.

Bill Gaither was born in Alexandria, Indiana, in 1936 to George William Gaither and Lela Olga Hartwell. He formed his first group the Bill Gaither Trio (consisting of Bill, his sister Mary Ann (1945–2018), and brother Danny Gaither (1938–2001) in 1956 while a college student at Anderson College, to which he had transferred after one year at Taylor University. He graduated from Anderson in 1959 with a major in English and a minor in music, after which he worked as an English teacher. He married the former Gloria Sickal in 1962.

Gaither earned his master's degree from Ball State in 1961, Gaither entered into the fledgling Gospel Music Association, founded in 1964, and helped organize the first Dove Awards ceremony in 1969.

He tried for a few years to manage both a music career and his full-time teaching job, but he quit his teaching job in 1967 and worked full-time in the Christian music industry. He recorded his breakthrough song "He Touched Me" in 1964.

Gaither was influenced by Southern gospel singers such as Jake Hess and Hovie Lister and by groups such as the Speers, the Statesmen, and the Happy Goodmans.

Gaither and his wife, Gloria, have written many songs including: "The Longer I Serve Him," "Because He Lives," "The King Is Coming," "Sinner Saved By Grace", "Something Beautiful," "He Touched Me", "It Is Finished," "Jesus, There's Something About That Name" "I'm Gonna Sing", and "Let's Just Praise The Lord." His songs have been performed by Christian artists (David Crowder Band, Carman, The Imperials, Sandi Patty, The Cathedral Quartet, The Speers and the Heritage Singers), country singers (The Oak Ridge Boys, The Statler Brothers) and pop artists (Elvis Presley). A video of a man surreptitiously recorded playing "Jesus, There's Something About That Name" on a piano in his destroyed house was shared by many people following the Tornado outbreak of December 10–11, 2021.

Gloria Gaither often writes the lyrics while Bill writes the music, although composing is usually a collaborative project between the two. As of 2005, they had composed 600 songs and by 2012 that number had increased to over 700.

After graduating high school, Gaither took a job in 1955 at Worthington, Ohio's radio station WRFD as a member of the station's gospel quartet. Since Gaither first began singing with the Bill Gaither Trio in the 1950s, he has constantly been performing. The trio originally consisted of Bill, his brother Danny Gaither and his sister Mary Ann Gaither. In about 1964 Bill's wife, Gloria, took the place of Mary Ann. The trio sang traditional gospel songs along with original compositions by the Gaithers that gave them a more contemporary feel.