A supporting actor performs roles in a play or movie other than that of protagonist. A female who performs these roles is usually referred to as a supporting actress.

These roles range from bit parts to secondary leads. They are sometimes but not necessarily character roles. In earlier times these were often ethnic stereotypes. The title is usually specific to the performance, that is, a person may be a supporting actor in one film and the leading actor in the next. An individual who typically plays supporting roles is considered a character actor.

Supporting roles may be pivotal or vital to the story. In recognition of important nature of this work, the theatre and film industries give separate awards to the Best Supporting Actor and actress.