A protagonist (from Ancient Greek πρωταγωνιστής prōtagōnistḗs 'one who plays the first part, chief actor') is the main character of a story. The protagonist makes key decisions that affect the plot, primarily influencing the story and propelling it forward, and is often the character who faces the most significant obstacles. If a story contains a subplot, or is a narrative made up of several stories, then each subplot may have its own protagonist.

The protagonist is the character whose fate is most closely followed by the reader or audience, and who is opposed by the antagonist. The antagonist provides obstacles and complications and creates conflicts that test the protagonist, revealing the strengths and weaknesses of the protagonist's character, and having the protagonist develop as a result.