John Nash (18 January 1752 – 13 May 1835) is a British architect responsible for much of the layout of Regency London under the patronage of George IV first as Prince Regent then king.

He is also a pioneer in the use of the Picturesque in the design of buildings and their layout.

His most famous designs are the Royal Pavilion, Brighton, and Buckingham Palace (though the facade to the mall is not Nash's work).