"Leader of the Pack" is a 1964 pop song recorded by girl group The Shangri-Las. It became number one on the Billboard Hot 100 on November 28, 1964.

The tune was credited to producer George "Shadow" Morton with Jeff Barry and Ellie Greenwich. According to Morton, he wrote the song for the Goodies (also known as the Bunnies), but instead it was needed as a follow-up to the Shangri-Las hit "Remember (Walking in the Sand)". Morton claimed he credited Barry and Greenwich as co-writers for business reasons; his recollection has been questioned by Ellie Greenwich.

In July 1964, Morton recorded the vocals for the song with the Shangri-Las at the Ultrasonic Sound studio on the second floor of a Manhattan hotel. These vocals were dubbed over the instrumental parts which had been previously recorded at the Ultrasonic Recording Studios in Hempstead, New York. Billy Joel, then a young session musician, claimed he played piano on "Leader of the Pack", but this has been denied by Greenwich. In fact, the piano part was played by Roger Rossi, a staff musician for Ultrasonic Recording Studios at the time. Rossi said, "I remember the date like it was yesterday, there were no written charts, so unfortunately, some musicians kept making mistakes. As I recall, it took 63 recording takes before Shadow Morton was satisfied." Rossi added, "By the end of the session, in take 62, I also messed up and Morton laughingly yelled out, Ohhhh, noooo. Not you, too!!"

According to legend, to add the authentic sound of a motorcycle engine, one was driven through the lobby of the hotel and up to the floor of the recording studio. No one was arrested, but a ticket was issued. However, in an interview four decades later, Shangri-Las lead singer Mary Weiss said the motorcycle sound was taken from an effects record. The Zombies' drummer Hugh Grundy recalls revving up a motorcycle backstage when the Shangri-Las performed on a U.S. tour.

In the United Kingdom, the song was refused airplay by the BBC, probably due to its death theme, although some have speculated that it was considered likely to encourage violence between mods and rockers. It still charted four times in the UK between 1965 and 1976, peaking at number 3 in 1972 (by which time the BBC ban had been lifted). The record also reached number 1 in Australia. In 1990, it featured in the soundtrack of the Martin Scorsese film Goodfellas.

In 2004, Rolling Stoneranked the song among the 500 Greatest Songs of All Time, at #447.

The song is about a girl named Betty, asked by friends to confirm that she is dating Jimmy, the leader of a motorcycle gang. After singing of love at first sight (" I met him at the candy store/He turned around and smiled at me/You get the picture?/That's when I fell for the Leader of the Pack"), Betty's heart turns to despair as she bemoans her parents' disapproval. The parents claim Jimmy hails from "the wrong side of town" and will be a bad influence on her. They ask Betty to tell Jimmy goodbye and find someone new.

Betty does as she is asked, and an upset Jimmy — after putting up his bravado — speeds off on his motorcycle. Moments later, Jimmy crashes on a rain-slickened surface and dies; Betty's pleas for Jimmy to slow down were in vain. In the end, Betty is left to deal with heartbreak but vows never to forget her fling with Jimmy, the "Leader of the Pack."