- The following is a list of secrets, easter eggs, and hidden trivia references in Grand Theft Auto III.
- For a list of Myths, see GTA Myths Wiki.
- In the very southwestern block of Bedford Point lies a parking lot (notably featured in the Kingdom Come mission) where an easter egg can be located; known as The Hidden Sign. To reach it, the player needs a car of small size such as Manana or Taxi. Going up the stairs leading to an overlooking platform to the north of the lot (near the entrance to an underground parking in the same area), the player must jump from the car to reach the top of a building to the west, jump down on the wall and from there drop down to an otherwise inaccessible alley behind it. At the end of the alley, on the wall, there is a posted notice that states "You weren't supposed to be able to get here you know." Near the poster is a ramp that allows the player to leave again.
- If you leave the city limits of Liberty City by using the Dodo you can see in the radar various Rockstar Games' programmers edited to seem town names e.g. Obbeburgh (Obbe Vermeij), Aaronsville (Aaron Garbut), Woodcunty (Alisdair Wood), Les County (Leslie Benzies), Garystown (Gary McAdam) and Adamton (Adam Fowler or Adam Cochrane).
- There is a billboard that says "See you in Miami!", this a hint of where the next game would take place Grand Theft Auto: Vice City which is based on Miami.
References to previous games
- Top Down City is a fictional film in GTA III. Ads can be spotted all over the city. The film is a reference to Grand Theft Auto 1, and Grand Theft Auto 2 as these two are in the Top-Down Perspective.
- Inside of the TW@ Internet Cafe there are computers on the first floor displaying screenshots of GTA 1, and GTA 2.
References to other games
- On the in-game radio, you can sometimes hear references to Carcer City, which is a city that would be later used in Rockstar's Manhunt.
- In the mission Two-Faced Tanner the character that the player has to kill is named Tanner, protagonist of the Driver series. He was given a female walking animation due to the criticism that Tanner in Driver walked like a girl.
- Badfellas is another film advertised in GTA III. It is a parody of the film Goodfellas which Frank Vincent, the voice of Salvatore Leone starred in.
- Rockstar Games are known for hiding their logo in secret places in their games. There is, however, a poorly disguised Rockstar Games logo on top of a unusable helicopter on the roof of Kenji's Casino. The logo is poorly disguised because it even reads 'Rockstar Games' below it. The logo can also be found on a hat of the pedestrian that wears headphones (and is famous for the mysterious tune heard through them).
- In Staunton Island, there is a store with a banner above its enterance. The banner is a Rockstar Games' self advertisement banner as it reads GTA 3 OUT NOW and WWW.ROCKSTARGAMES.COM.
- The yellow notebooks carried by male students of Liberty Campus feature scribbled drawings of urinating male genitalia.