A type, with a lowercase "t", refers to the three main types of cards: Monster, Spell, and Trap. Two more types, Virus and Trap-Spell, have been featured in the manga, and a Spell variant, Speed Spell, has been featured in some video games.

Certain cards, such as "Ordeal of a Traveler", when mentioning the term "type" in their effect, usually specify "monster, spell or trap" in brackets after the term to avoid confusion with monster Types.