In Street Fighter III: 2nd Impact there is an unused female voice that doesn't match either Elena or Ibuki. It's possible these voice lines belonged to an earlier version of Makoto, as she was originally meant to debut in this game but was moved to 3rd Strike due to time constrains.

There's a sprite of popular anime character Doraemon hidden in the background of Gill's stage. To actually see the sprite in-game, first the player has to perform a glitch to get Alex and Chun-Li onto Gill's stage. Right after that they have to do several glitches including one involving Alex and Chun-Li's throws to get the latter at an unnaturally high point. If Chun-Li stomps on Alex she will fly up into the air and the background will eventually loop vertically, revealing the Doraemon sprite.

In a 2003 interview with the game's producer Noritaka Funamizu published in the 15th Anniversary Street Fighter limited edition DVD set, Funamizu stated that at the time he had been pushing Yoshiki Okamoto to include Chun-Li in the game, and Okamoto agreed to it, if 3rd Strike were to be developed. At the time, the team thought of making a big roster for 3rd Strike, and Okamoto was more insistent. He also stated that if Chun-Li wasn't included in the game, she wouldn't have gained the same impact as before. Okamoto thought of Chun-Li as the mascot of Capcom.

Funamizu also stated that Chun-Li's absence was the team's number one complaint they received from players for not including her in the previous Street Fighter III games. However, he stated that the team did wanted to include her in the games.

Urien's ending in Street Fighter III: 3rd Strike was going to be somewhat different, as seen in early storyboards.

The storyboards show that the building of the secret society was going to be a modern skyscraper in the middle of a city while the final game shows a building similar to the Tower of Babel in the desert.

Additionally, the ending featured a giant sphere containing the brains of past Illuminati leaders. This was replaced in the final game with tubes containing the bodies.

One of Elena's rotoscoped animations in Third Strike was modeled after an actress in the music video to David Lee Roth's cover of "Just a Gigolo / I Ain't Got Nobody".

In a 1999 developer interview published in Gamest magazine, the concept art for Ibuki's "Yami Shigure" move was originally going to be a normal special attack, but was changed to Super Art after many people complained.

Originally, Ken was going to have more moves, but that idea was scrapped, due to his "Shoryuken" move being too strong.

Makoto was originally planned to be introduced in "Street Fighter III 2nd Impact: Giant Attack", but time restrictions led to her not being included.

The hand sings used by Oro during his animations for blocking/parrying an attack, using his normal fireball, or using his Yagyou Dama super art, are know as mudra, which are symbolic or ritual gestures from the Hindu and Buddhist faiths; later on incorporated into various eastern styles of martial arts. Additionally, Oro draws Ki energy from a specific part of his body depending on where his hand is placed, for example, if Oro placed his hand on his head he's drawing energy from the brow chakra, and when placed on the chest he's drawing energy from the heart chakra.

During the development of the game, Twelve was originally going to morph into Abigail from the Final Fight series when using X.C.O.P.Y against Hugo.

According to the "ALL ABOUT Capcom Fighting Games 1987-2000" book, Alex was originally supposed to be the main character of SF3, but this was changed because he wasn't recognized as a hero character compared to Ryu.

Chun-Li makes a cameo in Ryu's background during the New Generation and 2nd Impact games; she can be seen bathing on the top left of the stage.

One of Chun-Li's win quotes in the game is "Hey leave me alone. I'm a fighter, not a news reporter." This may refer to the Street Fighter live-action movie, where Chun-Li was portrayed as a news reporter.

Screens from early versions of the game show that Ryu originally had different art at the select screen. This early version also has different colors on the HUD, and the "PLAYER SELECT" text was blue instead of yellow.

Checking in the sound test reveals that all of the Super Art moves for each character have the garbling effect (used when the character Twelve transforms via X.C.O.P.Y) recorded for them, even though the use of the Super Gauge as a timer means that Twelve cannot use any of his opponent's Super Arts in-game. This possibly indicates that Twelve was going to be able to use Super Arts from his opponents at one point.

In the game's data there is a remix of the "Jingle Bells" Christmas song that goes unused in normal gameplay. This music was most likely used in a location test build of the game, which had Christmas and New Years messages for the player. As these messages were removed from the final version, the Jingle Bells theme also goes unused, although you can still play it in the sound test.

A prototype version of Hugo can be found in the game data for Street Fighter III: New Generation, with only his basic moves finished and placeholder graphics. Performing certain attacks on him may cause him to become invisible or freeze the game.

In the Japanese version of Street Fighter III: 3rd Strike and 2nd Impact: Giant Attack, when Urien loses to his opponent by time out, he squeezes his arm, which spurts out blood. The blood was removed in the International version.

When a character obtains a full bar of their super meter in 3rd Strike, the phrase "Let's Go!" can be heard. This is actually a sample from the 1960s Batman TV show; specifically the line "To the Batmobile! Let's Go!"

In the Japanese version of Street Fighter III: 2nd Impact, "Akuma's" blood is red in his defeated portrait, but in the International version, they colored it in green.

In Street Fighter III: New Generation, when loading the main menu the game also loads in an unused image for a ghost that looks very similar to the Ghosts from Pac-Man.