Bland hans många historiska skrifter märks "George Canning and his times" (1903), "England since Waterloo" (1913), "The eastern question: a study in european diplomacy" (1917), "English history in Shakespeare" (1918), "England under the Tudors" (1922) och avdelningen "Our own times" i samlingsverket "These eventful years" (1924). Marriott skrev bland annat "Second chambers" (1910), "Syndicalism: economic and political" (1921) och "Economics and ethics" (1923).