* ActorAllusion:
** [[Creator/ScottMcNeil Zizrar, King of the Mole People]], who has a very similar voice to a certain iguana, said at the end of Season 3, "[[WesternAnimation/KryptoTheSuperdog Man, I hate that kid and super dog!]]"
** [[Creator/JamesArnoldTaylor Johnny]] wants to be a [[Website/YouTube SnoobTube]] [[http://www.youtube.com/user/JamesArnoldTaylor sensation.]]
* AdoredByTheNetwork: The show was constantly getting new episodes and reruns, despite having a ''huge'' {{Hatedom}}. Eventually the network [[OurProductSucks got sick of it as well]], but found they had no choice but to keep making it thanks to certain Canadian laws.
** Christmas Day 2014 was "Johnny Test-Mas"---a marathon of Johnny Test, including episodes that weren't aired before the show was cancelled. [[TrollingCreator Way to spread some holiday cheer, CN.]]
** It's just as bad in Canada, since Season 2 and beyond are produced for Cancon. However, Creator/{{Teletoon}} airs [[SeasonalRot Seasons 2 and 3]] over and over again, but enjoys the show as much as [[Creator/CartoonNetwork the American broadcaster]]. Season 1 has never aired there, likely because Teletoon doesn't own the rights to the [[ScrewedByTheLawyers American-produced Season 1]].
* ChannelHop: From [=CW4Kids=] (formally Kids WB) to Cartoon Network, made official with the fourth season.
* LostEpisode: The first six episodes of the series with Johnny's original voice actor (who is still unnamed to this day) cannot be found anywhere.
* MoneyDearBoy: Supposedly, this was why the series lasted so long despite having a large {{Hatedom}}. Compared to other shows, ''Johnny Test'' was incredibly cheap to make, so much so that even with the bare minimum of people watching it, Creator/CartoonNetwork could ''still'' turn a profit on it. Considering it primarily aired when Cartoon Network was going through hard times, it's believed this fact was what caused it to become AdoredByTheNetwork despite its haters, simply because no matter ''what'' time-slot they put it in, they could always profit off of it, and use it to fill airspace when they couldn't afford to do so with other shows. In essence, ''Johnny Test'' filling airtime while still turning a profit was what allowed other, more expensive shows like ''WesternAnimation/AdventureTime'', ''WesternAnimation/RegularShow'', and ''WesternAnimation/StevenUniverse'' to see the light of day. And, notably, once the channel was able to handle itself again, ''Johnny Test'' was canned not long afterwards.
* ScrewedByTheLawyers: One of the possible factors in the show's deterioration and eventual cancellation. Apparently, Scott Fellows created the show along with TV producer David Straiton in 1996, but couldn't score a TV deal for it. Years later, Fellows got the show on TV anyway without crediting or paying Straiton, which led to Straiton suing him for fraud and accounting malfeasance.
* TheOtherDarrin:
** In Season Five, Louis Chirillo has been replaced with Creator/TrevorDevall. It's very noticeable, with the voice pitch changed completely and Trevor struggling to keep the same inflections with obvious throat pain (going by the rough, scratchy noises). And for all his effort, he just ends up sounding like Hugh Test.
** Mary was voiced by Brittney Wilson in Season 1 before [[Music/HeyOcean Ashleigh Ball]] took over. For whatever reason, Brittney returned for Season 5 before Ashleigh resumed the role again for Season 6.
** The original pilot used to pitch the show used American voice actors (with Creator/JamesArnoldTaylor as Johnny Test) before switching to Canadian voice actors for the series proper. Despite this, James kept his role since the Canadian voice actor that replaced him didn't sound close enough to his voice, and so he redubbed the dialogue and kept his role for the rest of the series.
* WhatCouldHaveBeen: A full-length movie was actually considered at one point. The series has been cancelled for years, so it will probably never get made.
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