"Hang On Sloopy" is a song by the pop group The McCoys which was #1 in America in October 1965 and is the official rock song of the state of Ohio and The Ohio State University. It was written by Wes Farrell and Bert Russell and is named for singer Dorothy Sloop (1913-1998), who used the name "Sloopy" on stage.

The song was originally titled "My Girl Sloopy" and was first recorded by The Vibrations in 1964 on Atlantic Records (45-2222), becoming a top thirty hit. It was the title track of a live 1965 recording (released on Rhapsody in 1966) by the Ramsey Lewis Trio which earned a gold record. It has also been recorded by The Ventures (Liberty 1965) as well as by Arseno Rodriguez (Bang 1966), The Supremes (Motown 1966), The Kingsmen (WAND 1966), Little Caesar and the Consuls, The Yardbirds, Saving Jane, Jan & Dean (Liberty-LP "Folk'n'Roll" 1965), David Porter (Enterprise "Into A Real Thing" 1971) and Die Toten Hosen (2002). It has also been performed by Johnny Thunders and the Oddballs in a medley with "Louie Louie" and can be heard on the "Add Water and Stir" live Japan bootleg.

In 1965, The Strangeloves, a rock band who purported to be from Australia, decided to make the song the follow-up to their hit single "I Want Candy", and began performing the song in concert. However, the Dave Clark Five, whom they were touring with, told the Strangeloves that they were going to record their own version of the song, copying the Strangeloves' arrangement. The Strangeloves realized that the Dave Clark Five's version would probably outsell their own, but they were still enjoying success with "I Want Candy" and did not want to release a new single yet. So the trio—who were, in reality, three successful writer/producers from Brooklyn, New York— recruited a group from Union City, Indiana, Rick and the Raiders, to record the song instead. The group's name was changed to The McCoys (to avoid confusion with another popular band of the era, Paul Revere and the Raiders), and their 16-year-old leader, Rick Zehringer, became known as Rick Derringer. The group added vocals and a guitar solo to the already-completed Strangeloves backing track, and the single was released on Bang Records. It entered the chart on August 14, 1965, effectively beating the Dave Clark Five to the charts. The single went on to hit number one on October 2.

Originally written and recorded with three verses, "Hang On Sloopy" was edited down to two verses for the single and original Hang On Sloopyalbum. The unedited three-verse version first appeared on the 1970 Bang various artists compilation Bang & Shout Super Hits(BLPS-220), then again in 1995 on the Sony Legacy compilation Hang On Sloopy: The Best Of The McCoys

The song gained an association with The Ohio State University after its marching band began playing it at football games; it first played it October 9, 1965 after a band member, John Tatgenhorst, begged the director to try playing it. After finally convincing the director, Tatgenhorst arranged the song and the band played. After the crowd reaction, the band began to play it at every game and now it is a Saturday tradition to play the song before the start of the fourth quarter of every Buckeye game. Since then, "Sloopy" has been appearing on the band's CDs and as a free download on its website.

The song has also become a feature at all Cincinnati Bengals and Cleveland Browns home games where, as is the case at Ohio State, it is traditionally played before the fourth quarter. The Cincinnati Bengals have been phasing the song out, due to their large Kentucky fan base. Fans usually chant the letters "O, H, I, O" during the pauses in the chorus while mimicking the shape of the letters with their arms. It is also often done at home games of the Cleveland Cavaliers and Cleveland Indians. The Cleveland Browns, Cleveland Indians and, the Columbus Blue Jackets use the song the most, along with Ohio State University.

The "O, H, I, O" chant was incorporated into a version of the song recorded by the Columbus, Ohio based rock band Saving Jane. The song was also a staple of Big Bear grocery store commercials in the Columbus area

At least one source includes a possible connection between the song and Charles J. Givens

Bruce Springsteen and the E Street Band also covered this song live in concert on May 2, 2009 in Greensboro, North Carolina.

The basic riff of the song became a staple of garage bands during the 1960s, being used on such songs as The Weeds' "It's Your Time" and Kit and the Outlaws' "Dude and the Sundowners" "Don't Tread on Me." The song was covered by The Beau Brummels on the band's 1966 album Beau Brummels '66. A 1973 cover version by Ramsey Lewis won the Grammy Award for Best R&B Instrumental Performance in 1974. Punk rock band, Youth In Asia (New Jersey) recorded the song on their 1984 album Pulling Out The Plug. A parody named "Hang on Snoopy" was included on Swiss rock group Patent Ochsner's 1994 album Gmües. All-girl Japanese punk band Lolita No. 18 covered the song, which is a testament to its far-reaching influences. The song was also covered by the German punk-rock band Die Toten Hosen as b-side for their 2000 single "Bayern." Also in 2000, Aaron Carter recorded his version, included as a bonus track on his second album, Aaron's Party (Come Get It). In 2006, the rock group Saving Jane recorded the song also. There is a character in the novel The Wanderersby Richard Price named "Hang On Sloopy." The song also appears in several Peanutscartoons but the words are altered slightly to "Hang on Snoopy". The family of the late Bert Russell Berns call their music publishing company Sloopy II Music. In Mexico was covered by the Rock & Roll group Los Teen Tops (The Teen Tops)and known as "Lupita mi Amor" (Lupita, My Love). The Smashing Pumpkins also released a cover of the song in their Live Smashing Pumpkins album series. Islands (band) uses the chorus in a b-side named "Two Dogs."

"Sloopy" is commonly misheard as "Snoopy" in the song (Snoopy is a dog from the comic strip Peanuts by Charles Schultz).

In April 1985, a columnist for the Columbus Citizen-Journal, Joe Dirck, saw a wire service story about a proposal to designate "Louie, Louie" the state rock song of Washington and wrote a column about it. This goaded the 116th Ohio General Assembly into action and it designated "Hang on Sloopy" the state rock song by House Concurrent Resolution 16 on November 20, 1985, with clauses including:

and

"Hang on Sloopy" is now also the official song of the Major League Baseball team the Cleveland Indians who play at Progressive Field in Cleveland, Ohio. The song is played during the middle of the 8th inning. It was chosen in response to a tradition in many ballparks of choosing an 8th inning song for the fans and team. It has received overwhelming support from the fanbase and has high participation.

"Hang On Sloopy" was used as the entrance song for deaf fighter Matt Hamill at UFC 96.