| Term | Definition |
| Mario | The hero of all Mario games. |
| Luigi | Mario's little brother. |
| Donkey Kong | The monkey that throws barrels at Mario |
| E.Gadd | A Scientist that usually helps out Mario and his friends with useful inventions |
| Pauline | the woman whom Mario must rescue from the titular ape in the original Donkey Kong |
| Peach | the princess of the Mushroom Kingdom |
| Daisy | a tomboy princess |
| Donkey Kong Jr. | The son of the original Donkey Kong |
| Poochy | A dog-like creature, is a friend and possible pet of Yoshi |
| Toad | A humanoid mushroom that is both a single character and the collective name of the "Mushroom People" found in the Mushroom Kingdom. |
| Toadette | is a member of the Toad species that appears as a playable character in various spin-off games |
| Toadsworth | an elderly Toad steward of Peach, |
| Yoshi | A dinosour with a long sticky tongue that also makes eggs |
| Birdo | A femine looking dinosour that is really a guy and spits eggs out of it's nose |
| King Boo | A large ghost with a crown, blue tongue and red eyes |
| Bowser | referred to as King Koopa and is Mario's archnemesis |
| Bowser Jr. | The son of bowser |
| Kamek | is a Magikoopa and was also Bowser's caretaker back when Bowser was a child and is currently one of his high-ranking minions. |
| Waluigi | He is the same age as Luigi and is his darker rival |
| Wario | He is the same age as Mario and is his darker rival |
| Bloopers | Squid-like beings |
| Bomb-omb | Living circular black bombs possessing limbs |
| Boo's | spectral beings resembling traditional Halloween ghosts, |
| Bullet Bill | large, black missile-like enemies, |
| Bully | enemies that resemble bob-ombs, but lack fuses and instead have two horns around the size of there body |
| Buzzy Beetle | are blue shelled, tortoise-like creatures commonly found in underground locations |
| Chain Chomp | are black, spherical dog-like creatures, often shown to be restrained by chains |
| Cheep Cheep | are red and yellow fish (although other colors such as green and blue exist) with white undersides |
| Dry Bones | skeletal Koopa Troopas reanimated by the desceased Koopa Troopa's spirit inhabiting its bones |
| Goomba | brown mushroom-like creatures with feet, bushy eyebrows, and a pair of fangs sprouting from their lower jaw |
| Hammer Bros | Are from the Koopa Troopa race commonly found in pairs who wear helmets and utilize hammers as their main weapons |
| Koopa Troopa | a turtle like being, is the most common classification of Koopa. Koopa Troopas are the standard troopers of the Koopa Army who work for Bowser |
| Lakitu | is a Koopa with a green shell, orange or yellow body, glasses or goggles with thick black frames, and is usually seen flying in a cloud bearing a smiling face. |
| Magikoopa | are from the Koopa Troopa race wearing a blue hat and robes, as well as spectacles. Magikoopas attack by firing spells that can not only injure Mario, but transform certain blocks into enemies |
| Monty Mole | species of mole that are characterized by hiding and waiting for an enemy before attacking |
| Paratroopa | are Koopa Troopas, but have feathery wings and need to be jumped on twice before being defeated. |
| Piranha Plant | is a Venus fly trap-like enemy, almost always portrayed as a leafy green stalk topped with a white-spotted red globe, almost bisected by a white lip mouth with razor-sharp teeth. |
| Pokey | is a cactus monster |
| Shy Guy | small masked beings that appear in various colors. |
| Snift | are beings that resemble Shy Guys with a black mask with an extended nozzle that can fire bullets from these nozzles. |
| Thwomp | are cubical animated blocks of stone, depicted as having angry-looking faces and clenched teeth. |
| Wiggler | are caterpillar-like insects with a segmented body and comically large nose |