Dion Francis DiMucci (born July 18, 1939), better known mononymously as Dion, is an American singer-songwriter whose work has incorporated elements of doo-wop, pop oldies music, rock and R&B styles—and, most recently, straight blues. He was one of the most popular American rock and roll performers of the pre-British Invasion era. He had more than a dozen Top 40 hits in the late 1950s and early 60s. He is best remembered for the 1961 singles, "Runaround Sue" and "The Wanderer", written with Ernie Maresca.

Dion's popularity waned in the mid-1960s, perhaps due to the public's changing taste in pop music, and perhaps in part due to personal difficulties he had during this period. But toward the end of the decade, he shifted his style and produced songs with a more mature, contemplative feeling, such as "Abraham, Martin and John". He became popular again in the late 1960s and into the mid-1970s, and he has continued making music ever since. Critics who had dismissed his early work, pegging him as merely a teen idol, praised his later work, and noted the influence he has had on other musicians.