Dion Francis DiMucci (born July 18, 1939), better known mononymously as Dion, is an American singer and songwriter whose music has incorporated elements of doo-wop, rock, R&B and blues. Initially as lead singer of Dion and the Belmonts, and then in his solo career, he was one of the most popular American rock and roll performers of the pre-British Invasion era. He had 39 Top 40 hits in the late 1950s and early 1960s as a solo performer, with the Belmonts or with The Del-Satins. He is best remembered for the singles "Runaround Sue", "The Wanderer", "Ruby Baby" and "Lovers Who Wander", among his other hits.

Dion's popularity waned in the mid-1960s. Toward the end of the decade, he shifted his style and produced songs that were more mature and contemplative, such as "Abraham, Martin and John". He became popular again in the late 1960s and into the mid-1970s and has continued making music since. During the 1980s, Dion produced several Christian albums. He returned to secular music in the late 1980s with Yo Frankie (1989). Between the mid-2000s and 2020, Dion released five Top Blues Albums. Critics who had dismissed his early work, labeling him as a teen idol, praised his later work and noted the influence he has had on other musicians.

Dion was inducted into the Rock & Roll Hall of Fame in 1989.