"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 30 times. The song was originally composed in E-flat major (following an 8-bar introduction in B major). In the 1961 and 2021 film adaptations, both introduction and chorus were lowered by a whole step.
The song is widely known for its use of the melodic interval of a tritone in the main theme. This is also a major motif throughout the other songs in the musical. The song is an example of the use of Lydian mode, which is the same as the major scale but with a raised 4th.