Young Justice was an American animated television series created by Greg Weisman and Brandon Vietti for Cartoon Network. Rather than being based on the comic book series of the same name, the series was an adaptation of the DC Universe as a whole with a focus on a group of teenage heroes and sidekicks known as The Team.
References in Teen Titans Go!
In "Sidekick", on his DCUbook status feed, Robin likes a status from Blue Beetle, reading "Eatin' some burgers. WHAAAT!!! #SaveYoungJustice" and cools it, referencing the campaign to renew the series for a third season.
In "Missing", Beast Boy is reading a Young Justice comic book with Kid Flash on the cover saying, "I'M BAAAACK!" alluding to his death in "Endgame".
In "Más y Menos", during the clip explaining Más y Menos' powers, a video on the playlist is titled Young Justice: The Movie with a line-up of the 2010 incarnation of The Team and 1,234,567 views.
In "Salty Codgers", Robin is reading the same Young Justice comic book that Beast Boy read in "Missing".
"Let's Get Serious" will crossover Young Justice and Teen Titans Go!, with the heroes showing up to chastise the Titans for giving superheroes a bad name. Artemis and Kid Flash were hinted at appearing due to their voice actors recording lines "for old times sake", but it has since been confirmed for audio commentary accompanying the Season 1 Blu-ray release.