A character actor is a supporting actor known for small parts who plays unusual, interesting, or eccentric characters. The term, often contrasted with that of leading actor, is somewhat abstract and open to interpretation. In a literal sense, all actors can be considered character actors since they all play "characters", but the term more commonly refers to an actor who frequently plays a distinctive and important supporting role. Character actors are generally well-known and recognizable by the audience (by appearance if not by name), even if they play different types of roles in different movies.

A character actor may play characters who are very different from the actor's off-screen real-life personality, while in another sense a character actor may be one who specializes in minor roles. In either case, character-actor roles are more substantial than bit parts or non-speaking extras.

The term is used primarily to describe television and film actors, as opposed to those in the theater. An early use of the term was in the 1883 edition of The Stage, which defined a character actor as "one who portrays individualities and eccentricities". Actors with a long career history of playing character roles may be difficult for audiences to recognize as being the same actor.