The Mermaid Theatre was a theatre encompassing the site of Puddle Dock and Curriers' Alley at Blackfriars in the City of London, and the first built in the City since the time of Shakespeare. It was, importantly, also one of the first new theatres to abandon the traditional stage layout; instead of this, a single tier of seats surrounded the stage on three sides.

Puddle Dock is a street in Blackfriars in the City of London. It was once the site of one of London's docks, and was later the site of the Mermaid Theatre. The dock was filled in during redevelopment in the 1960s and 1970s.