|Birth name||Justin Gunnar Walter Chancellor|
|Born||September 19, 1971|
|Instruments||Bass guitar, guitar|
Justin Gunnar Walter Chancellor is an English musician formerly in the band Peach but best known as the bass player for progressive metal band Tool. Chancellor is of English and Norwegian descent. After settling in the US, along with his engagement in his musical projects, he and his wife Shelee Dykman Chancellor ran a store called Lobal Orning in Topanga, California, dedicated to music and literature "that shaped and changed" both of them. The store closed in 2008. He started M.T.Void music project with Piotr "Glaca" Mohammed from Sweet Noise. In October 2012, Chancellor featured as bass player on the song "In the Spirit Of..." on The Fusion Syndicate album, released by Cleopatra Records. His track also appears on the 2014 album The Prog Box.
Chancellor was educated at Tonbridge School in Kent, England, where he was the bass player for a school band named Slice of Life and used to perform a cover version of Corey Hart's "Sunglasses at Night" in the dining room of his boarding house. The band released an eponymous titled tape featuring a song of the same name. Chancellor went on to study at Durham University. He later joined the band Peach.
Peach released an album and supported Tool in the early 1990s in England. In September 1995, Chancellor moved to the United States and joined Tool full-time to replace Paul D'Amour who departed during or after the recording of the band's second full-length album. Chancellor has been a full member of the band since the 1996 studio album Ænima.
- Wal – Chancellor’s main bass is a Wal 4-string he bought on a friend’s recommendation during the recording of Ænima. The bass’s woods and electronics help create the midrange cut and punch for which he is known. Justin also has three other four-string Wals. Justin normally plays Ernie Ball Hybrid Slinky strings (.045, .065, .085, .105)
- Music Man Stingray – Used on "Forty-Six & 2", "H.", "Pushit" and "No Quarter".
- Gibson Thunderbird – Used once for "Prison Sex" live in 1995/1996, when he first joined the band.
- Warwick Streamer - As of 2017, Justin has his own custom shop Streamer Stage II bass.
- Gallien-Krueger 2001RB head x3 (1 Dirty, 1 Clean, 1 Spare)
- Mesa Boogie Roadready 4x12 (For Dirty)
- Mesa Boogie Roadready 8x10 (For Clean)
- Demeter Amplification VTBP-201S Bass Preamp running direct to PA
- Formerly used
- Mesa Boogie M-2000 head
- Mesa Boogie M-Pulse
- Mesa Boogie Bass 400+
- Mesa Roadready 8x10 (in place of the 4x12)
- Boss TU-2
- Guyatone VTX Tremolo
- DigiTech Bass Whammy – Used on "Eulogy" (fifth up/sixth up harmony), "Pushit (Live)" (fifth up/octave up harmony), "Third Eye" (octave up), "Schism" (octave up), "Ticks and Leeches" (fifth up/octave up harmony), "Lateralus" (octave up), "Disposition" (fifth up/octave up harmony), "Vicarious" (octave up harmony), "The Pot" (octave up), "Right in Two"(fifth up/sixth up harmony), and "Invincible" (octave up).
- Tech 21 SansAmp GT2 Distortion
- Boss CE-5 Chorus Ensemble
- Boss BF-2 Flanger
- Boss DD-3 Digital Delay
- MXR Bass Envelope Filter
- Prescription Electronics Rx Overdriver
- Colorsound Tone Bender Fuzz
- Foxx Fuzz/Wah/Volume-Volume Pot Removed 
- Chancellor played bass on the Isis song 'Altered Course' on their 2004 album Panopticon. Chancellor also provided additional sounds/bass guitar on the Isis song, "Weight" from their 2006 live Clearing the Eye [DVD].
- Additional bass on the title track of Intronaut's 2010 album, Valley of Smoke.
- Chancellor narrated on the Primus track "The Valley" from their 2017 album The Desaturating Seven.
- In May 2018, Chancellor collaborated with Death Grips in the album Year of the Snitch, providing bass on the track "Disappointed".
- Mahaffey, Joel (6 August 2001). "The Tool Page: Justin Chancellor Biography". The Tool Page (t.d.n).
- "TOOL: The Collective Unconscious". Toolarmy.com. Archived from the original on 7 January 2009. Retrieved 24 August 2014.
- "The Fusion Syndicate (CD) | Cleopatra Records : Store". Cleorecs.com. Retrieved 24 August 2014.
- "The Gear of Tool: The Instruments Behind the Alt-Metal Masters' Sound". reverb.com. Retrieved 30 July 2020.
- January 2020, Jon D’Auria08. "Tool's Justin Chancellor gives an inside look at the band's next album". Bass Player. Retrieved 30 July 2020.
- "Live video of Primus performing The Valley with Justin onscreen".
- Yoo, Noah (15 March 2018). "Death Grips Working With Tool's Justin Chancellor on New Album". Pitchfork. Retrieved 12 May 2019.