主人公（也称主角）是小说、戏剧、影视作品和ACG作品中故事的主要人物（中心或首要人物）。在电影及相关奖项中，主人公则被分为男主角和女主角。

主人公是叙事的中心人物或视角的出发点。

大部分作品通常只注重在于突出或表现男性主人公，女性人物则作为陪衬；市面上只有少数着力刻画，真正的女性主人公的作品。

正面的主人公通常具有许多美德，如英勇果敢、坚定不移、敢于牺牲等，是榜样式的正面英雄形象。也有反面的版本，如地狱男孩/地狱男爵里的男性主人公。惊险小说、动作电影等的主人公通常聪明敏捷、身手不凡，且有逢凶化吉的好运。

The word protagonist (fromAncient Greekπρωταγωνιστής (protagonistes), meaning "player of the first part, chief actor") has more than one definition which can be found in the dictionary. It is used notably in stories and forms of literature and culture that contain stories, which would include dramas, novels, operas and films. In those forms the definition may simply be the leading actor, or the principal character in the story. But in addition the word takes on more formalized definitions. For example, the protagonist, while still defined as a leading character, may also be defined as the character whose fate is most closely followed by the reader or audience, and who is opposed by a character known as the antagonist. The antagonist will provide obstacles and complications for the protagonist; the antagonist will create conflict, which will test the protagonist — thus revealing the strengths and weaknesses of their character.