Glenn Douglas Barnard Cornick (23 April 1947 – 28 August 2014) was an English bass guitarist, best known as the original bassist for the British rock band Jethro Tull from 1967 to 1970.

Rolling Stone has called his playing with Tull as "stout, nimble underpinning, the vital half of a blues-ribbed, jazz-fluent rhythm section".

They were replaced by Jon Blackmore (guitar and vocals) and Jeff Jones (ex-Man) (drums) who joined Cornick, Tweke and Pickford-Hopkins to record Wild Turkey's first album Battle Hymn - which only reached number 193 in The Billboard 200.

[10] Cornick then joined the German band Karthago, with whom he recorded just one album, Rock'N'Roll Testament, before leaving and moving to Los Angeles to form Paris, with guitarist Bob Welch (ex-Fleetwood Mac) and Thom Mooney (ex-Nazz) on drums.

They were joined by Graham Williams (ex-Racing Cars) (guitar), John "Pugwash" Weathers (percussion) and former Jethro Tull drummer Clive Bunker, all of whom had played with Cornick in the past.