Abraham Isaac "A.B." Quintanilla III (born December 13, 1963) better known as A.B., is an American songwriter, record producer and musician. He is the older brother of "The Queen of Tejano music" Selena. Along with Selena, his other sister Suzette, and his father Abraham, he became a member of Los Dinos in 1980 which would later include Selena's husband Chris Pérez as a guitarist. As a member of Los Dinos, A.B. would play bass guitar, produce and write songs for Selena which became successful singles such as "Como La Flor", "Amor Prohibido" and "No Me Queda Más".
A.B.'s sister, Selena, was murdered on March 31, 1995. He helped produce "Como Te Extraño" (How I Miss You) by Pedro "Pete" Astudillo, which was written for Selena as well as Astudillo's late grandmother. The song earned Astudillo a Premios Lo Nuestro award for Best Song of the Year in 1996.
He produced and arranged the 2004 CD, A.B. Quintanilla III Presents Joe Lopez, which includes "Cuando Estoy Contigo" [When I Am With You] and "Soy Tan Feliz" [I'm So Happy], co-written by Quintanilla and Luigi Giraldo.