The trench Buzz Lightyear flies through in the opening sequence is the Ant Island set modified to make the river bed deeper. Some pebbles were accidentally left floating in midair, but the crew liked how it looked and kept it in.
Early in the film, when Rex loses to Zurg at the Buzz Lightyear video game, the calendar that can be seen on the wall behind him has an image of the ant colony gathering food.
When Mr. Potato Head finds Mrs. Potato Head's missing ear, Mrs. Potato Head is reading the novelization of A Bug's Life.
In Al's Toy Barn, toys of the characters from A Bug's Life can be seen hanging on the shelves.
During Jessie's flashback sequence, the tree that Emily and Jessie play on bears a resemblance to the tree from Ant Island.
Flik and Heimlich appear in the outtakes, where Flik believes Heimlich to have talked Pixar into making A Bug's Life 2. Heimlich then admits to Flik that Pixar is making a 2 movie, but it's not A Bug's Life 2. The branch they stand on then gets chopped down by Buzz Lightyear.
This is in reference to Heimlich's actual cameo in the film, where he's briefly glimpsed before Buzz breaks through the vegetation as they reach the street where Al's Toy Barn is located.
In Toy Story 3, when Woody crawls out from the ceiling in the day care center over the Catepillar room, the letters ATTA can be seen on the wall.
Near the beginning of Up, the tree that Carl and Ellie go to to look at the clouds bears a resemblance to the tree from Ant Island.
In the Yes, Dear episode, "Are We There Yet?", the Warner and Hughes families go on vacation to the Grand Canyon in a run-down RV that the Hughes family rents. At one point, Kim mentions that Dominic, Logan, and Sammy planned to watch Toy Story, but decided to watch A Bug's Life instead. Not the movie, but an actual bug's life.
Whose Line Is It Anyway?: During the "Props" segment of Episode 414, Wayne uses his prop as makeshift antennae and claims to be a character from A Bug's Life.
The Office (US): At one point in "Threat Level Midnight", Michael says that he thought A Bug's Life was much better than Antz.
Jury Duty: Ronald shows Todd, a fellow juror who feels ostracized for his wacky inventions, A Bug's Life in order to show him that people who invent world-changing things are often not understood at first by the rest of society. Todd responds by wearing chair pants to the next day of jury duty.
In Gex 3: Deep Cover Gecko, a throw-away sign in the Slappy Valley hub area says, A Bug's Wife.
In LEGO The Incredibles, Flik is an unlockable character, unlocked by building P.T. Flea's Circus Wagon in Urbem Heights. Flik can dig and attack by throwing dirt clods.
In Mickey Mouse Reacts, when Mickey reacts to a paint-scraping video in which the paint appears to be covered with live bugs, he yells "This is not A Bug's Life!"
The Nostalgia Critic: In his review of The Brave Little Toaster, during the scene where Toaster is Ground by Gears as he saves his friends and their master from being crushed at the junkyard, the Critic plays a clip from the film where Francis faints after seeing Dot's school play of the Warrior Bugs.
In the sketch, "A Bug's Short Life" from the Robot Chicken episode, "Choked on a Bottle Cap", the characters from A Bug's Life cannot get any sleep because the Mayflies themselves are partying, having sex, giving birth, going through a midlife crisis as husband and wife, and finally dying in the span of three hours. Dave Foley reprises his role as Flik for the sketch.
In the The Simpsons episode, "Helter Shelter", Homer hires the "A Bug's Death" extermination company to fumigate his house when it was infested with termites. When Marge asks him why he hired them, he tells her that he found the logo funny.
, Jason winds up covered with spider webs and says, "I see where they got the idea for A Bug's Life."