- "The Puerto Rican Connection", which is a lot like the famous chase scene in The French Connection. Furthermore, "Three Leaf Clover" is a lot like the bank heist in Heat.
- The very first mission is called The Cousins Bellic.
- The story about "children with their hands chopped off" is most probably a reference to Kurtz's famous monologue in Apocalypse Now.
- The Addiction Level "Bummed In The Gob" is a throwback to a meme from the Edge forum/rllmuk/Consolevania lineage. The phrase was coined by a Scottish games reviewer while reviewing the first Manhunt Game (also by Rockstar) who described the game: 'You spend a lot of time getting killed in the face and bummed in the gob'. Hilarity ensued.
- The ringtone "Katja's Waltz" is a Suspiciously Similar Song of "Lara's Theme (Somewhere, My Love)". For a Genius Bonus and a bit of foreshadowing, "Katja" is a Slavic version of "Kate".
- One mission is called: "I Need Your Clothes, Your Boots, and Your Motorcycle."
- The Republican Space Rangers is an obvious shout out to Halo and Gears of War.
- One of the available dates, Alex Chilton, shares the name of the frontman for Big Star.
- Alex Chilton may also be a reference to the song "Alex Chilton" by the Replacements, which was named after the previously mentioned singer.
- Alex's name may also be a reference to Paris Hilton.
- Playboy X's unique yellow Patriot◊ emulates a yellow Hummer◊ featured in the Steven Seagal movie Exit Wounds.
- Several visuals reference The Great Gatsby: the Sprunk sign in Dukes is written in the same font as the Pepsi sign in The Film of the Book, and in Hove Beach there's an optometrist's sign with a pair of glasses-wearing eyes, a nod to the Eyes of Dr. T.J. Eckleburg.
- Niko bears a strong resemblance to the character Sasha (played by Vladimir Mashkov) in Behind Enemy Lines. There's even an ensemble you can purchase from the Russian Shop that is a dead ringer for Sasha's track outfit. Compare.◊ Mashkov further confirmed in an interview that he was approached by Rockstar to play "a man with a dark past, with a slightly rumpled appearance" in an unnamed video game. Mashkov declined the role due to sparse details which he found uninteresting. Only later did he learn that the game was GTA IV.
- There are rare, randomly appearing paintjobs for the Coquette◊ and the Huntley Sport◊ that emulate The A-Team's Chevy Corvette and GMC Vandura respectively.
- Stevie has you steal a unique Super GT◊ that comes in a shade of gray that makes it look a lot like the Aston Martin DBS introduced in Casino Royale (2006).
- Dialogue (both involving main characters and random pedestrian discussions), radio shows and TV programs are loaded with Mythology Gags to GTA III-era games such as Vice City and San Andreas. CJ, the lead character from San Andreas, appears on a billboard, while an outfit worn by Claude from Grand Theft Auto III is unlocked if you kill Playboy X.
- An easy one to miss: sometimes, while riding in a taxi, the driver will say something along the lines of "I'm just like the Cash Cab; I'm not a real taxi driver."
- There exists a 'Big Boss' nightclub in Chinatown.
- During one of Brucie's helicopter rides, while looking at the Rotterdam Tower (Empire State Building), Brucie may comment "If I were that big chimp, I'd climb it too!"
- The first trailer was a homage to Koyaanisqatsi, showing everyday life in Liberty City set to "Pruit Igoe" which is also featured on the in-game soundtrack.
- In the main directory under naturalmotion folder had Fred and Wilma art files.
Shout Out / Grand Theft Auto IV