The Mercury Theatre (1937–1946) was an independent repertory theatre company founded in New York City by Orson Welles and producer John Houseman.

Mercury Theatre may also refer to:

• Mercury Theatre, Notting Hill Gate, London, 1933–1987
• Mercury Theatre, Colchester, England, opened 1972

• Mercury Theatre, Auckland New Zealand theatre, founded 1910
• Mercury Theatre (Australia), renamed by actor Peter Finch

• The Mercury Theatre on the Air, (originally titled First Person Singular), a 1938 radio drama anthology series created by Orson Welles