This article documents the relationship of Gary the Snail and Squidward Tentacles. Being SpongeBob's pet snail, Squidward hates Gary, and the latter returns the favor. Squidward is so careless about Gary that he almost killed him in "I Was a Teenage Gary."
Despite their rivalry, there have been a few peaceful moments between the two, though said moments tend not to last very long.
The first time that Squidward and Gary interact is in "Culture Shock," in which Squidward allows Gary to be in the Krusty Krab talent show. Another soft moment between the pair is in "Giant Squidward," where they share the same opinion about SpongeBob being annoying when he gives them an oversize limb; Squidward listens to Gary’s story and replies in an understanding tone "Oh, tell me about it!" Another time is in "That Sinking Feeling," where Squidward searches for SpongeBob in his house and says "hi" to Gary upon spotting him on the roof and the latter returns the greeting.
- In "I Was a Teenage Gary," Squidward says to SpongeBob that he will feed Gary, only to act negligent towards him and enjoy his SpongeBob-free vacation, causing Gary to nearly die of hunger and thirst.
- In "Can You Spare a Dime?," Gary calls Squidward a free loader as the latter calls him other bad names.
- In "The Great Snail Race," he forcefully races against Squidward's snail, Snellie.
- In "Once Bitten," Squidward makes many anti-snail wooden logs. A log somehow gets stuck inside Gary's foot and he gets a splinter. Gary goes out of control because the splinter or log is uncontrollably painful; Squidward is the first to get bitten.
- "The Thing" reveals that Gary violently attacked Squidward once. When Squidward turns into the thing, Gary attacks Squidward again.
- In "Patty Caper," when SpongeBob blames Gary for supposedly stealing the Krabby Patty secret formula, Gary describes another suspect—Squidward. Based on the picture Patrick had drawn of Squidward, Gary must think Squidward is very ugly.
- In "Little Yellow Book," he bites Squidward's tentacle in a flashback because he was badmouthing SpongeBob.
- In "Unreal Estate," Gary attacks Squidward when the latter sneaks into SpongeBob's bedroom at night to clog his alarm clock with pepper.
- In "Chatterbox Gary," Gary, using his new translation collar, criticizes Squidward's artwork and calls him naïve, which provokes an angered reaction from Squidward. To get revenge, Squidward sneaks into SpongeBob's house at night and replaces the translation collar with a walkie-talkie, using it to give commands to a tired SpongeBob, ultimately resulting in SpongeBob's house rolling down a road. When a now homeless SpongeBob is suggested by the walkie-talkie to dig a hole, Gary notices Squidward behind a brick wall and realizes that he was responsible for the loss of SpongeBob's house, prompting him to take the walkie-talkie and kick it into Squidward's throat, making him sound like Gary that causes a bunch of worms to angrily chase and attack him.