Juliet Capulet (in Italian Giulietta Capuleti) is one of the title characters in William Shakespeare's tragedy Romeo and Juliet, the other being Romeo Montague. The story has a long history that precedes Shakespeare himself. The heroine's wealthy and rich family lived in Verona, headed by Lord and Lady Capulet. She was their youngest child. She apparently had older siblings at some point, but by the time of the play, she was their only surviving child. Juliet is the sole heir to the Capulets. As a child, she was cared for by her nurse, who is now her confidante, or Juliet's caretaker. As the story occurs, Juliet is approaching her fourteenth birthday (her sixteenth in Arthur Brooke's poem). She was born on "Lammas Eve at night" (August 1), so Juliet's birthday is July 31 (1.3.19). Her birthday is "a fortnight hence", putting the action of the play in mid-July (1.3.17).

Shakespeare's Juliet was very young; her father states that she "hath not seen the change of fourteen years" (1.2.9). In many cultures and time periods, women did and do marry and bear children at such a young age. However, in Shakespeare's England, most women were at least 21 before they did so. Romeo and Juliet is a play about Italian families. The average English playgoer in Shakespeare's audience had never met an Italian person, and it was commonly thought that they were quite exotic, the Italian male passionate and emotional, and the Italian female precocious and quite ready to become a mother by thirteen. Lady Capulet had given birth to Juliet by the time she had reached Juliet's age: "By my count, I was your mother much upon these years that you are now a maid" (1.3.74-75). The play celebrates youth while pointing out its impulsiveness, passion, and idealism; qualities which contribute to the tragedy. The adolescent infatuation of the lovers becomes elevated to the status of sacred love.