The Adelphi Theatre is a 1500-seat West End theatre, located on the Strand in the City of Westminster. The present building is the fourth on the site. The theatre has specialised in comedy and musical theatre, and today it is a receiving house for a variety of productions, including many musicals. The theatre was Grade II listed for historical preservation on 1 December 1987.
It was founded in 1806 as the Sans Pareil ("Without Compare"), by merchant John Scott, and his daughter Jane (1770–1839). Jane was a British theatre manager, performer, and playwright. Together, they gathered a theatrical company and by 1809 the theatre was licensed for musical entertainments, pantomime, and burletta.