Monmouth Street is a street in the Seven Dials district of Covent Garden, London, England.
Monmouth Street runs north to south from Shaftesbury Avenue to a crossroads with Tower Street and Shelton Street, where it becomes St. Martin's Lane. About halfway it meets Seven Dials, where it intersects with Mercer Street, Earlham Street, and Shorts Gardens. It is numbered B404.
Notable inhabitants in 1751–55 included the freemasons John Hamilton and John Holland.
The Covent Garden Hotel is situated at no. 10.
Pollock's Toy Museum started in 1956 in a single attic room at No. 44 above Benjamin Pollock's Toy Shop, but outgrew the premises and moved in 1969 to Scala Street.