"Maria" is sung by the male lead Tony when he learns the name of the girl he's fallen in love with is "Maria". The name "Maria" is spoken or sung in the song 27 times. It begins in B major and then modulates to E-flat major.
The song is widely known for its use of the melodic interval of a tritone in the main theme. The song is an example of the use of lydian mode, which is the same as the major scale but with a raised 4th, giving the tritone characteristic of this piece.