A Guest Strip is a episode of a webcomic that was not drawn or written by the current authors of said webcomic. Due to the communal nature of the Web and webcomics culture, this is much easier to organise than in other media. It is, perhaps, ascended FanArt.

Usually, guest strips are [[CanonDiscontinuity Non-Canon]] and posted as FillerStrips. Entire "Guest Strip Weeks" are often invoked by webcomic authors when they need back surgery, a week in Tahiti, an opportunity to deal with familial issues, or a chance to attend a [[FanConvention Con]]. Other comics, usually dailies, post a guest strip on Sundays in lieu of an elaborate SundayStrip.

Nearly ''all'' webcomics have done this at some point; it's something of a NecessaryWeasel.
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!!Examples:

* ''{{Drowtales}}'' uses this to not only lessen the work load on the main artist of the comic, but to use the different art styles to fully show off the current narrative. These strips are just as professional grade as the main comic and just as canon as art done by the main artist, advancing the story along in their absence.
* One special event in the history of guest strips occurred on September 17th, 2007. During the previous month, webcomic author Ryan Estrada drew an entire 48 guest strips for 48 different webcomics - by itself an impressive feat. What's more, he contacted all 48 authors of the 48 webcomics and got them to post each of his guest strips ''on the same day''. So it was that, on a bright sunny morning in September, many webcomic fans woke up to find Ryan Estrada's artwork on dozens upon dozens of their favourite webcomic sites.
** And guess what? He did it ''again'', on September 18th, 2008 - but with ''70'' guest strips this time. Seventy guest strips. One of those guest strips was for a [[ShowWithinAShow Comic Within A Comic]]. One of those guest strips was for a ''news blog''.
* Inverted in the case of Webcomic/{{xkcd}}'s [[http://xkcd.com/141/ Parody Week]], where Randall Monroe drew five [[TheParody parodies]] of some of his favourite webcomics and posted them as part of his own webcomic.
** XKCD did a guest strip week in November 2010, when Randall was struggling with a family illness.
* ''Webcomic/AndShineHeavenNow'' has never missed a day in part because every break on the author's part is filled with guest strips. This has the interesting effect of limiting the length of any hiatus to the number of filler strips the readership can be coerced to produce.
* ''Webcomic/{{Avalon}}'' was once advertised in the Keenspot newsbox as featuring "the most comics drawn by other people."
* In the twelve or so year history of ''Webcomic/PennyArcade'', the need for a guest strip has only come up once, after a PAX convention where the artist came down with swine flu (and then only because he was physically incapable of lifting a pencil to draw). The illness was incorporated into some of the strips.
** And again half a year later when "There was a point after PAX East had come to a close and the second leg of our book tour was underway that we began to understand we had fucked up."
* Webcomic/DinosaurComics has a guest week once a year or so.
* For some reason ''Webcomic/BillTheBarbarian'' has a '''truckload''' of these.
* ''Webcomic/FiveColorControl'' uses them occasionally.
* ''Webcomic/ElGoonishShive'' had [[http://www.egscomics.com/index.php?arcid=61 a week of them]] after the Painted Black arc and [[http://www.egscomics.com/?date=2006-10-02 another]] after the Birthday Party arc. Dan has done [[http://litbrick.troutcave.net/comic.php?date=2011-01-08 three]] [[http://litbrick.troutcave.net/comic.php?date=2011-10-24 of]] [[http://litbrick.troutcave.net/comic.php?date=2011-10-28 them]] himself for ''Webcomic/LitBrick''.
* Inverted on ''Webcomic/TheWordWeary'': After weeks of asking for guest comics and presumably getting no replies, John Kossler, the author, made three guest strips for himself and posted them under different names. At the end of the week, he [[http://wordwearycomic.blogspot.com/2011/10/9-october-2011.html admitted as such.]]
* ''Webcomic/{{Femmegasm}}'' has had several due to the creator's health problems.
* ''Webcomic/EvenInTheDeepestHeartOfChaosAGlimmerOfOrderCanBeFound'' has a lot of these, since any random person can create one, as the comics are an auto-generated selection of photos found on Flickr with captions written by the enterprising author.
* There have been two guest strips in ''Webcomic/EarsForElves'' so far, with the characters but nothing related to the plot. [[http://www.earsforelves.com/archives/578 The first]] was an "exchange" with the artist of ''DoodlingAround'', so Naarie also drew a guest strip for that webcomic; [[http://www.earsforelves.com/archives/630 the second]] was a comedy strip by the artist of ''SuckerPunchToMyEmotions''.
* [[http://www.anticscomic.com Antics]] by Stephen Gillian has had a few: [[http://www.anticscomic.com/?p=265 here]], [[http://www.anticscomic.com/?p=267 here]], [[http://www.anticscomic.com/?p=974 here]], [[http://www.anticscomic.com/?p=1025 here]], and [[http://www.anticscomic.com/?p=1082 here]].
* ''Webcomic/TheDailyDerp'' has on two occasions featured fan comics from Website/DeviantArt. There was also [[http://dailyderp.tumblr.com/post/34218118360/tetrapony-late-daily-derp-provided-by-a-great a comic drawn by the author's friend]] and [[http://dailyderp.tumblr.com/post/37314419567/luna-thou-going-to-share-thy-muffin another drawn by Tsitra360 when the author was sick.]]
* ''Webcomic/GunnerkriggCourt'' did a strange example where ''the characters'' made [[http://www.gunnerkrigg.com/?p=1168 a series of guest strips]] mutually forming the third installment of "City Face," the surreal adventures of a talking pigeon. Bringing things up to total MindScrew level, [[http://www.gunnerkrigg.com/?p=1176 one of the guest strips]] was done by the author of the comic.
-->"Today's update was written by me, Tom."
* ''WebComic/{{Precocious}}'':
** During the "Party crashers" arc, while Chrispy had a broken finger. The guest artists included Matt Dawson (''SometimeAlone''), Brooke Eggleston (''AlsoBagels''), Irene Pitcairn (''SunElves''), [[http://www.soulgamer.deviantart.com/ Robert McConnell]], Carl Sjostrand (''[[GingersBread Ginger's Bread]]''), [[http://ndunlimited.com/ Terrence and Isabel Marks]], John Peters (''GypsygirlPress''), and [[http://www.nox07.deviantart.com/ Roman Utkin]] (who does a [[http://furries.ru/precocious/ Russian translation]] of ''Precocious'').
** A new set of guest strips began in March 2013, with a couple of twists on the theme.
* As an April Fools joke for 2013, ''Webcomic/BreakpointCity'' and ''Webcomic/CrunchyBunches'' switched artists, with Scott drawing ''[[http://www.breakpointcity.com/archives/2013/04/01/syrup-up-and-away/ Syrup, Up, and Away,]]'' and Brian drawing ''[[http://www.crunchybunches.com/comic/a-normal-april-comic/ A Normal April Comic]]''.
* Sam Logan occasionally holds [= O-GAWDs =] (Obligatory Guest Artist Webcomic Duration), week-long sessions of ''Webcomic/SamAndFuzzy'' strips drawn by a variety of other artists, such as ''Webcomic/QuestionableContent'' 's Jeph Jacques, or ''Webcomic/WastedTalent'' 's Angela Melick.

!Non-webcomic examples
* The [[http://en.wikipedia.org/wiki/Comic_strip_switcheroo Comic Strip Switcheroo]] of April 1, 1997, where 18 pairs of cartoonists drew comics for each others' strips as an April Fools' joke.
* ''ComicStrip/{{Dilbert}}'' had [[http://search.dilbert.com/comic/Guest%20Cartoonist a week of guest strips]] in 2003.
* ''ComicBook/FishPolice'', while under the publication of Comico, had guest strips in the back called "Fish Shticks". These were still written by Steve Moncuse, but drawn by guest artists.
* ''ComicStrip/CulDeSac'' had several weeks of guest strips in 2012, as Richard Thompson was getting treatment for Parkinson's Disease. (Thompson would end the strip later that year.)
* For a week in June 2014, Bill Watterson returned to newspaper cartooning by guesting on ''ComicBook/PearlsBeforeSwine''
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