During an interview with Variety Fair, Todd Howard revealed that the 2024 live-action "Fallout" TV series was considered canon to the games, having wanted to tell an original story within the game's world rather than adapt any of the previous games. However, when the show came out, this led to complaints from fans accusing the show of retconning the events of Fallout: New Vegas. Specifically, the sixth episode "The Trap" featured a shot of a blackboard seemingly depicting the fall of Shady Sands (the capital of the New California Republic) as taking place in the year 2277. Fallout: New Vegas takes place in the year 2281, yet Shady Sands is stated to still exist in the game without any mention of a fall (although the city cannot be visited in-game). Emil Pagliarulo, a design director for Bethesda, would try to assure fans on Twitter that Fallout: New Vegas is still considered canon, claiming to being overprotective of the series' lore and going as far as to post a timeline of the Fallout series. While the timeline not only featured both Fallout: New Vegas, the TV series, and also confirmed that Fallout Tactics: Brotherhood of Steel is considered canon to the series, it did not address the timeline inconsistency brought about by the blackboard scene in the show. This reportedly led some fans to accuse Bethesda of holding a grudge against Obsidian Entertainment for making what many fans consider to be the best Fallout game and using the show as a way to spite them. However, it's worth noting that there are three other possible explanations for the inconsistency:

• Whoever wrote "2277" was misinformed due to the post-apocalyptic setting forcing many to rely on guesswork for event dates.
• It could be a simple mistake in writing for a series with large amounts of lore to it.
• It could be a reference to the "Lonesome Road" DLC expansion for New Vegas, where the player is given the option to nuke the NCR, though there is no confirmation that this ending is canon.

Howard would later defend the TV series and insist the game is still canon in an interview with IGN, claiming he had an emotional reaction when the TV series writers brought up the idea of bombing Shady Sands (which he also clarified was not a nuclear bombing) and carefully talked through the decision with them. When asked specifically about the 2277/2281 inconsistency, his response was that they were "threading [the needle] tighter there" to make it land in the TV series, move the Fallout series forward, and insisted that the fall of Shady Sands took place just after the events of the game. He reiterated that Bethesda was careful about sticking to the series timeline, admitting that there "might be a little bit of confusion at some places" and claimed that what was most important to them was what was happening in the time period of the TV series.

Obsidian's Scott Everts attributes some of the performance issues and simplifcation present in the game to the fact it wasn't a PC exclusive.

The Feral Ghoul Roamer has an error when loaded into editing software. While this doesn't cause conflicts in the game itself, the model attempts to draw from a model labeled "mmm_ghoulvariant_v1.nif". This is one of the feral ghoul variants that appeared in the Fallout 3 mod Mart's Mutant Mod, suggesting that Obsidian Entertainment had experimented with it while developing new features for the game.

There was originally an NCR super mutant ranger named Chauncey stationed at Station Foxtrot. he was included in early builds of the game, but ultimately cut prior to release.

By using console commands during the ending slideshow it's possible to find a character called "Ron the Narrator", who is used to narrate the slides and other sections of the game.

He can be seen wearing Legion armour, and is based off the actual narrator, Ron Perlman.

As a unique pre-order bonus at K-Mart, buyers received four coasters representing the four major casino found in the game, The Ultra-Luxe, Vault 21, The Tops, and the Lucky 38.

The Mr. New Vegas radio show has unused news reports detailing the outcomes of each game ending, which cannot be witnessed as the game doesn't allow you to play past the ending due to the drastic differences the game world would experience based on the outcome.

Dennis Crocker was originally planned to be Caucasian, but his lines were voiced by a non-Caucasian voice actor so the developers changed the character's appearance accordingly.
His original design can still be seen on the collectors edition playing cards.

A Vault Boy image named "perk_survivalist" appears in the game files. It differs in appearance from the original survivalist perk (found in Fallout, Fallout 2, and Fallout Tactics), and its unclear what it would do as it was never implemented into the game though it seems to imply that the perk was originally planned to appear in New Vegas.

Despite a higher resolution texture being available in the game's resources, the Spiked Knuckles used by the player do not use the high resolution texture.

When playing as a character with low intelligence and speaking to the vagrant in Freeside while doing the quest "I Can Make You Care", using intelligence to inquire about weapons and other precious loot will cause him to speak clearly and intelligently, and to caution the player to avoid his current predicament.

This seems to be a reference to Torr from Fallout 2 who has a similar string of interactions with low intelligence players.

Matthew Perry was cast in Fallout: New Vegas due to being a fan of the previous game; Fallout 3. He also gave away a signed copy of Fallout 3, not because he was in it, but rather just because he claimed it was his favorite game.

A Wrecked Highwayman can be found half-submerged in mud and, upon finding it, one of two background songs from Fallout 2 ("My Chrysalis Highwayman" or "Gold Slouch") will play. The trunk is filled with Energy ammunition, making it a nod towards the Highwayman in Fallout 2, which used Energy ammo as a fuel source. The original idea for this encounter came from J.E. Sawyer, who originally planned it for the cancelled Van Buren game, which would have included the Tanker FOB in the trunk from Fallout 2.

If the player has the Wild Wasteland trait, and nukes both the NCR and Caesar's Legion at the end of the Lonesome Road DLC, the ending slide will Spoiler:quote Charlton Heston and show a picture representing the ending scene from the original Planet of the Apes.

In the "Dead Money" DLC, when entering the wine cellar near the bell tower from which the player triggers the Gala Event, the phrase "I AM NOT YOUR MUMMY" is scrawled on the central pillar. This is in reference to the Ghosts' gas masks and the two-part episode of Doctor Who, "The Empty Child and The Doctor Dances".

If the player chooses to arm Archimedes I and leave Fantastic alive, in the quest "That Lucky Old Sun", upon returning the player will find Fantastic wearing Legion armor and having just killed his co-worker, Ignacio Rivas, stating "Hey man, when in Rome."

A portrait of the mother and father of Fallout 3's protagonist, The Lone Wanderer, can be found in Vault 21, next to Sarah's bed.

The Child at Heart perk from Fallout 3 was set to return to New Vegas, but was ultimately cut, most likely because there are very few children in the game. Unused dialogue can still be found within the game's audio files, however.

The challenge "A Slave Obeys" requires the player to Spoiler:kill Mr. House with the 9 Iron or Nephi's Golf Driver. This is a reference to the original Bioshock, in which the player Spoiler:beats the game's main antagonist, Andrew Ryan, to death with a 9 iron while he repeats the words "A man chooses, a slave obeys."

The perk "In Shining Armor" doesn't actually do anything. The perk was supposed to give the player an additional +5 Damage Threshold against energy weapons while wearing any metal armor, and +2 while wearing reflective eyewear.

The perk doesn't provide any Damage Threshold boost due to the fact that the parameter that is referenced when checking the skill type of enemy weapons is "Energy" instead of "EnergyWeapons". This means that the function "IsWeaponSkillType" will never return a value that can activate the perk effect, because there is no weapon skill called "Energy".