Over the years, a variety of bands have made up the yearly lineups of Ozzfest, a yearly heavy metal music festival that usually tours the United States in summer.^[1]

• Main stage:

Black Sabbath, Judas Priest, Slayer, Dimmu Borgir, Superjoint Ritual, Black Label Society

• Second stage:

Slipknot, Hatebreed, Lamb of God, Atreyu, Bleeding Through, Lacuna Coil, Every Time I Die, Unearth, God Forbid, Otep, Devildriver, Magna-Fi, Throwdown, Darkest Hour, Disown

• Main stage:

Ozzy Osbourne (on select dates), System of a Down, Disturbed, Avenged Sevenfold (cancelled August 13), Hatebreed (cancelled August 9 and 13), Lacuna Coil, DragonForce

• Second stage:

Ozzy Osbourne (on select dates), Black Label Society, Atreyu, Unearth, Bleeding Through, Norma Jean

• Second Stage (rotating slots):

A Life Once Lost, The Red Chord, Walls of Jericho, Strapping Young Lad, All That Remains, Full Blown Chaos, Between the Buried and Me, Bad Acid Trip

• Main stage

Ozzy Osbourne, Lamb of God, Static-X, Lordi, Black Tide (started August 10)

• Second stage

Hatebreed,^[9] Behemoth, Nick Oliveri and the Mondo Generator (July 12–22), DevilDriver (started August 2), Egypt Central (August 2–8)

• Second stage (rotating slots)

Nile, Ankla, The Showdown, 3 Inches of Blood, DÅÅTH, In This Moment, Chthonic, Circus Diablo

• Main stage

Metallica, Ozzy Osbourne, Serj Tankian, Hellyeah, Jonathan Davis, Cavalera Conspiracy, Shadows Fall, Apocalyptica, In This Moment, All Star Dimebag Darrell Tribute

• Second stage

Sevendust, DevilDriver, Kingdom of Sorrow, Soilent Green, Witchcraft, Goatwhore

• Texas stage

The Sword, Drowning Pool, Rigor Mortis, The Destro, Within Chaos, Debri, Black Tooth

• May 11

Slipknot, Slash featuring Myles Kennedy and the Conspirators, Deftones, Maximum the Hormone, Man with a Mission, Fear, and Loathing in Las Vegas, The Treatment, Namba 69, crossfaith, Galneryus, Momoiro Clover Z, Knock Out Monkey, and Artema

• May 12

Black Sabbath, Tool, Stone Sour, Dir En Grey, Anthem, coldrain, Steel Panther, Mucc, AA=, Ningen Isu, Head Phones President, and fade^[12][13]

• November 21

Korn, Evanescence, Bullet for My Valentine, Noisemaker, VAMPS, ONE OK ROCK, Crossfaith, Corey Taylor, MEANING, Crystal Lake, and SiM

 *OPENING ACTS :Wrong City, NoisyCell, The Winking Owl, Unveil Raze

• November 22

Ozzy and Friends, Jane's Addiction, Hatebreed, A Day to Remember, Black Label Society, Babymetal, Fear, and Loathing in Las Vegas, 9mm Parabellum Bullet, Her Name in Blood, Ningen Isu, and OLDCODEX

 *OPENING ACTS : Animetal the Second, A Crowd of Rebellion, Kanojo in the Display, SALTY DOG

^[14]

• Ron Jeremy – introduced Coal Chamber before their set in 1996. Can be seen on the Ozzfest Live VHS (discontinued).
• Phil Anselmo – performed the song "Kill All The White People" with Type O Negative in 1997 at the Glen Helen Amphitheater in San Bernardino, CA.
• Henry Rollins – preceded the main stage with a spoken-word performance in 1997.^[15]
• Benji Webbe (ex-Dub War/Skindred) – appeared with Soulfly at their UK dates in 1998.^[16]
• Kerry King (Slayer) Performed Thunderkiss with Rob Zombie on June 16, 1999, at the Meadows Music Theater in Hartford Connecticut.
• Buckethead – played a few songs with Primus during their set on the Main stage in 1999, and did various stunts such as doing the "robot" and swinging around nunchaku.
• Evan Seinfeld – sang with Pantera on "Walk" in 2000 at the PNC Bank Arts Center.
• Verne Troyer – actor who played Mini Me, appeared onstage with Pantera at Pine Knob (now DTE Energy Music Theater) in Clarkston, Mi on July 12, 2000.
• Dino Cazares – joined Soulfly to perform "Eye For An Eye" at Ozzfest 2000.
• David Draiman – joined Memento to perform "Stare" at Ozzfest 2003 in Scranton, Pennsylvania.
• Corey Taylor – joined Soulfly to perform "Jumpdafuckup" at Ozzfest UK 2001, and also joined SiM to perform a cover of Radiohead's song "Creep" at Ozzfest Japan 2015.^[17]
• Tom Araya – joined Soulfly to perform "Terrorist" at Ozzfest UK 2001.
• John Dolmayan – appeared with Tool in 2002 at the Antwerp and Dublin dates, performing "Triad."^[18]
• George Oosthoek (ex-Orphanage) – appeared with Within Temptation during "The Other Half (Of Me)" at Nijmegen in 2002.^[19]
• Dave Lombardo – appeared with Slayer at Nijmegen in 2002 (filling in for Paul Bostaph who had an elbow injury) and also with Tool.^[19]
• Mike Bordin – performed with Tool at Donington and Nijmegen in 2002.^[19]
• Zakk Wylde – performed with Soil on "Halo" in 2002.^[20]
• Kelly Osbourne – performed with Andrew W.K. on "She Is Beautiful" in 2002.^[21]
• John Tardy and Frank Watkins performed a mini-set of Obituary songs at Ozzfest 2002 in West Palm Beach, Florida with Andrew W.K. and his band. Obituary drummer Donald Tardy was Andrew's touring drummer at the time.^[22]
• Dimebag Darrell and Vinnie Paul joined Disturbed onstage at Ozzfest 2003 in Alpine Valley, Wisconsin and played guitar and drums respectively for a version of "Walk"
• Rob Halford – appeared with Black Sabbath on August 26, 2004, in Camden, replacing an ill Ozzy.^[23]
• Howard Jones – appeared with Throwdown in 2004.
• Will Smith and Jada Pinkett Smith – appeared with Bury Your Dead in 2005.^[24]
• Harry Perry during the 2006 Ozzfests, would play sets with System of a Down. He was also seen playing his guitar with a portable amp around the venues during the second stage performances.
• Candace Kucsulain of Walls of Jericho appeared with In This Moment in 2007.
• John 5 appeared with Static-X in 2007.
• Randy Blythe from Lamb of God joined Hatebreed to perform "Perseverance" and "Doomsayer" at Ozzfest 2007.
• Kevin Talley filled in on drums for Devildriver
• King Diamond joined Metallica at Ozzfest 2008 and performed a medley of "Evil", "Curse of the Pharaohs", "Satan's Fall", "A Corpse Without a Soul", and "Into the Coven." This medley also appeared on Metallica's Garage Inc. cover album, as the track "Mercyful Fate."
• Chester Bennington joined Disturbed in 2001 to perform a cover of Pantera's "Walk".
• Buzz Osborne from the Melvins played guitar on a few songs with Tool during their performance in 1998.
• Yuto Miyazawa joined Ozzy Osbourne at Ozzfest 2010 for the first 6 shows to play "Crazy Train"
• Drowning Pool joined Nonpoint to play "Miracale" and "Bodies" at Ozzfest 2010 on August 24.
• Branden Schieppati of Bleeding Through appeared onstage with Avenged Sevenfold at the Chicago date of Ozzfest 2006 to perform their cover of Pantera's "Walk".
• Nikki Sixx of Mötley Crüe joined Rob Zombie & Marilyn Manson at Ozzfest 2018 for a cover of The Beatles Helter Skelter.^[25]
• Dino Cazares guitarist of Fear Factory performed a song with Slayer right after a set with Fear Factory in San Antonio, Texas at Retama Park July 11, 1999.