Amos Leon Thomas, Jr. (October 4, 1937 – May 8, 1999) was an American avant-garde jazz singer from East St. Louis, Illinois.

Thomas studied music at Tennessee State University. In the 1960s he was a vocalist for Count Basie, among others.

In 1969, he released his first solo album for Bob Thiele‘s Flying Dutchman label. Thomas is best known for his work with Pharoah Sanders, particularly the 1969 song “The Creator Has a Master Plan” from Sanders’ Karma album. Thomas’s most distinctive device was that he often broke out into yodeling in the middle of a vocal. This style has influenced singers James Moody, Tim Buckleyand Bobby McFerrin, among others. He said in an interview that he developed this style after he fell and broke his teeth before an important show. Some of the vocal style is classified as ‘jive singing’. (Ref: Leon Thomas Blues Band album).