Protagonist

Romeo

Romeo's name is in the title, a pretty good hint that he's important. His name is also the final word in the play. So it's definitely arguable that the play is the story of Romeo's relationship with Juliet.

Juliet

Some scholars and directors like to argue that the play is really all about Juliet. Romeo's around, true, but it's Juliet who undergoes the most dramatic transformation. She starts the play as a little girl and ends as a woman, and the audience gets to see her change every step of the way. After the opening scenes, Juliet also gets some of the play's best lines. And she's the one most often soliloquizing all alone in front of the audience – something done, in most Shakespeare plays, primarily by the protagonist. If you want to get down to it, some people think that Romeo is cute but kind of annoying, and that the real dramatic strength and sophistication of the play is in Juliet's character. After all, the Prince ends the play with the lines, "For never was there story of more woe / than that of Juliet, and her Romeo." So, the story is either about Juliet or Shakespeare just wrote that line for the snazzy poetic meter and the rhyme scheme…