| Year | Title | Artist | Notes |
| 1980 | Universal Juveniles | Max Webster | On the track Battle Scar, Lifeson along with fellow Rush band members, Geddy Lee and Neil Peart play their respective instruments with Lee performing co-lead vocals. |
| 1985 | Alien Shores | Platinum Blonde | Features Lifeson's guitar solos on two tracks including "Crying Over You" single. |
| 1988 | Serious Business | Greenway | Album by fellow Canadian Brian Greenway (of bands April Wine, Mashmakhan and the Dudes), featuring Lifeson on guitar on the first track and single "In The Danger Zone" |
| 1989/1990 | Smoke On The Water | Rock Aid Armenia | Charity single re-recording song by British rock band Deep Purple organised by frontman Ian Gillan, Lifeson played alongside many other musicians including members of Deep Purple, Pink Floyd, Yes, Queen, Iron Maiden, Black Sabbath, Led Zeppelin and ELP. |
| 1990 | Lost Brotherhood | Gowan | Lifeson plays guitar on this album by fellow Canadian Lawrence Gowan of Styx and also on the albums self titled single. |
| 1995 | Hip To The Tip - Live At The Orbit Room | The Dexters | Album by Canadian band The Dexters (house band of The Orbit Room, a bar in Toronto), the band featured Lifeson (under the pseudonym "Alex Dexter") and other members where called Lou, on Hammond B3, Peter on bass, Bernie on guitar and Mike on drums (all members were under the surname "Dexter.") |
| Ragged Ass Road | Tom Cochrane | Lifeson is credited with guitar and guitar solo on this album by fellow Canadian musician, Tom Cochrane. A frequent collaborator with Cochrane is early Rush bassist and vocalist Jeff Jones. |
| 1996 | Scenery And Fish | I Mother Earth | Lifeson played additional guitars on one track on this album by Canadian rock band I Mother Earth. |
| 1997 | Merry Axemas: A Guitar Christmas | Various | Lifeson played a version of "The Little Drummer Boy" on this Christmas oriented tribute album organised by fellow guitarist Steve Vai,[citation needed] also featured guitarists Joe Satriani, Joe Perry, Steve Morse, Jeff Beck and Eric Johnson. |
| 2006 | Born4 | Jakalope | Lifeson (credited as Alex Liefson under Jakalope 2) is credited as a performer on this album by Canadian group Jakalope and also co-wrote one track. |
| Have You Seen Lucky? | John Kastner | Lifeson is credited on this album by fellow Canadian John Kastner, Kastner is most famous for being a former member of hardcore punk band Asexuals. |
| Better Days | Edwin | Lifeson plays guitar on two track on this album by alternative rock singer Edwin, who also participated in Lifeson's solo project Victor 10 years prior. |
| 2007 | Fear Of A Blank Planet | Porcupine Tree | Lifeson plays a guitar solo on the first movement of one track of this album by English progressive rock band Porcupine Tree. His solo would later be re-imagined and performed by touring guitarist John Wesley in live shows. The album also features a contribution by King Crimson guitarist Robert Fripp. |
| 2008 | Fly Paper | Tiles | Lifeson plays various guitars on one track on this album by American prog rock band Tiles, including assorted textures, lead guitar, rhythm guitar and 12-string acoustic guitar. The album also features artwork and design from frequent Rush collaborator Hugh Syme. |
| 2014 | Disconnect | John Wesley | Lifeson plays guitar on one track on this album by American guitarist John Wesley, Wesley had performed with Lifeson on the previously mentioned song by Porcupine tree (when Lifeson contributed guitar and Wesley contributed backing vocals). |
| Come to Life | Keram | Lifeson is credited, alongside 4 other guitarists, with electric guitar on this album by Keram (full name Keram Malicki-Sánchez), who is a member of band Blue Dog Pict. |
| 2016 | RES 9 | Rik Emmett & RESolution9 | Lifeson is features on two tracks on this album by Rk Emmett of the Canadian rock band Triumph, one track on his own and on another with Dream Theatre frontman and fellow Canadian James LaBrie. |
| 2017 | Borrego | Marco Minnemann | Lifeson is featured on guitars on this album by German rock drummer and musician Marco Minnemann, who has performed with Steven Wilson, U.K. and Jordan Rudess, Lifeson plays guitars on 3 tracks (including one bonus track), and wrote one. He is credited with acoustic guitar, guitar reverse, and FX and guitar solos. |
| 2018 | Clone Of The Universe | Fu Manchu | Lifeson is credited with additional guitars on one track on this album by America stoner rock band Fu Manchu. |
| Walking In The Wild Land | Jim McCarty | Lifeson is credited with lead guitar on one track on Yardbirds member Jim McCarty. The album also features keyboards from Rush collaborator Hugh Syme. |
| A Holiday Greeting From West End Phoenix | Various | Christmas release featuring vocals from Lifeson and Lee. |
| 2019 | My Sister | Marco Minnemann | Lifeson is credited as a special guest on this album by German drummer Marco Minnemann, he is credited with writing and with electric and acoustic guitars on two tracks and additional guitars on one. |
| Nobody Told Me | John Mayall | Lifeson is credited (along with other guitarists, including Joe Bonamassa, Todd Rundgren and Steven Van Zandt) on this album by legendary blues and rock singer and musician John Mayall. He plays guitar on one track. |
| American Rock 'N' Roll | Don Felder | Lifeson is credited with rhythm acoustic and solo electric on one track on this album by former Eagles lead guitarist Don Felder. The album also features Chad Smith, Slash, Mick Fleetwood and Joe Satriani. |
| Atheists And Believers | The Mute Gods | Lifeson is credited with 12-string guitar, ambient guitar and mandolin on this album by The Mute Gods, a progressive rock project formed of Nick Beggs (bass, chapman stick, guitar keyboads and vocals known for performing with Steve Hackett and Steven Wilson), Roger King (keyboards and guitar, known for performing with Steve Hackett) and Marco Minnemann (drums and guitar) |
| 2020 | II | McStine & Minnemann | Lifeson performs on this album by musicians Randy McStine (guitar, bass, keyboards, vocals) and Marco Minnemann (drums, perucussion, guitar, keyboards and bass). He performs guitar on the final track. |
| Eternity Now | Big Sugar | Lifeson performs guitar on the first and self titled track on this album by Canadian rock band Big Sugar. |
| 2021 | The Atlas Underground Flood | Tom Morello | Lifeson plays guitar and wrote (alongside Kirk Hammett of Metallica) on one track on this album by Rage Against the Machine member Tom Morello. |
