Little Theatre in the Adelphi was a theatre in London, on what is now John Adam Street just west of the Royal Society of Arts. It should not be confused with either the Haymarket Theatre or the Adelphi Theatre both of which are in the West End. The theatre was constructed in 1910 from a banking hall previously used by Messrs Coutts, part of the original Adam Brothers Adelphi development between the Strand and the River Thames.