The character selection out of each game has been back and forth, so here's a list of all the characters ever playable, and which games they appeared in. The list will order the characters by their first appearance in the series. Exceptions will be listed in parentheses.
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!Introduced in:

!!VideoGame/SuperMarioKart
* Bowser
* Donkey Kong Jr. (Has never appeared in any other game, possibly because ''VideoGame/DonkeyKongCountry'' was released after this game and Nintendo decided to use Donkey Kong afterwards instead.)
* Koopa Troopa (Has only appeared in ''Double Dash!!'', ''Wii'', ''7'', and ''8''.)
* Luigi
* Mario
* Peach (Referred to as "Princess" in Super Mario Kart only.)
* Toad
* Yoshi

!!VideoGame/MarioKart64
* Donkey Kong
* Wario

!!VideoGame/MarioKartSuperCircuit
No new characters, the roster is the same as ''64''.

!!VideoGame/MarioKartDoubleDash
* Baby Luigi (Has only appeared in ''Wii'' and ''8''.)
* Baby Mario (Has only appeared in ''Wii'' and ''8''.)
* Birdo (Has only appeared in ''Wii''.)
* Bowser Jr. (Has only appeared in ''Wii'' and ''Arcade GP DX''.)
* Daisy (Did not appear in ''Arcade GP'', ''Arcade GP 2'', and ''Arcade GP DX''.)
* Diddy Kong: (Has only appeared in ''Wii''.)
* King Boo (Has only appeared in ''Wii''.)
* Paratroopa (Has not appeared in any other game.)
* Petey Piranha (Has not appeared in any other game.)
* Toadette ([[RememberTheNewGuy First appearance ever]], has only appeared in ''Wii'' and ''8''.)
* Waluigi (Did not appear in ''Arcade GP'' and ''7''.)

!!VideoGame/MarioKartArcadeGP
* [[VideoGame/PacMan Blinky]] (Has only appeared in ''Arcade GP 2''.)
* [[VideoGame/PacMan Ms. Pac Man]] (Has only appeared in ''Arcade GP 2''.)
* VideoGame/PacMan: (Has only appeared in ''Arcade GP 2'' and ''Arcade GP DX''.)

!!VideoGame/MarioKartDS
* Dry Bones (Has only appeared in ''Wii''.)
* R.O.B. (Has not appeared in any other game.)
* Shy Guy (In ''DS'', he is only playable through DS download-play. He has also appeared in ''7'' and ''8''.)

!!VideoGame/MarioKartArcadeGP2
* [[VideoGame/{{Tamagotchi}} Mametchi]] (Has not appeared in any other game.)

!!VideoGame/MarioKartWii
* Baby Daisy ([[RememberTheNewGuy First appearance ever]], has only appeared in ''8''.)
* Baby Peach (Has only appeared in ''8''.)
* Dry Bowser (Has not appeared in any other game.)
* Funky Kong (Has not appeared in any other game.)
* Mii (Has only appeared in ''7'' and ''8''.)
* Rosalina (Has only appeared in ''7'', ''Arcade GP DX'' and ''8''. In ''DX'', she is a downloadable character.)

!!VideoGame/MarioKart7
* Lakitu (Has only appeared in ''8''.)
* Metal Mario (Has only appeared in ''8''.)
* Queen Bee (Referred to as "Honey Queen" in ''7''. She has not appeared in any other game.)
* Wiggler (Has not appeared in any other game.)

!![[http://www.mariowiki.com/Mario_Kart_Arcade_GP_DX Mario Kart Arcade GP DX]]
* [[VideoGame/TaikoDrumMaster Don-chan]] (Has not appeared in any other game.)
* Fire Mario (Has not appeared in any other game.)
* Ice Luigi (Has not appeared in any other game.)

!!VideoGame/MarioKart8
* Baby Rosalina ([[RememberTheNewGuy First appearance ever]])
* Iggy Koopa
* Larry Koopa
* Lemmy Koopa
* Ludwig Von Koopa
* Morton Koopa Jr.
* Pink Gold Peach ([[RememberTheNewGuy First appearance ever]])
* Roy Koopa
* Wendy O. Koopa
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