John Wayne Carroll (December 19, 1929 – January 25, 2013), usually known as Gregory Carroll or Greg Carroll, was an American R&B singer, songwriter, and record producer. He was a member of several successful vocal harmony or "doo-wop" groups including The Four Buddies and The Orioles, and co-wrote and produced Doris Troy's 1963 hit "Just One Look".
He was born in Baltimore, Maryland, one of six children of Upsher and Sally Carroll. He formed a vocal group, The Metronomes, with three school friends from Frederick Douglass High School in Baltimore, Leon "Larry" Harrison, William Carter and Vernon Palmer. The group recorded, with Johnny Otis among others, for Savoy Records, and changed their name, first to the Four Buds and then the Four Buddies. Carroll was the second tenor voice in the group. In 1951 they had a no.2 national hit on the Billboard R&B chart with the song "I Will Wait".
He left the Four Buddies in 1953 and replaced George Nelson as second tenor in the Orioles, shortly before the group recorded their biggest hit, "Crying in the Chapel". The song reached no.1 on the R&B chart and no.11 on the pop chart. After the Orioles split up in 1955, Carroll developed an interest in music production, while also working as a background singer on sessions in New York City. He also reunited with Larry Harrison to form another vocal harmony group, The Dappers. They signed with RCA Records in early 1956, but the original group split up after their first recording and Carroll recruited a new group, who recorded for Rainbow Records and toured as The Dappers.