Arnold House School is a preparatory school for boys in the St John's Wood district of Westminster, Greater London.

Arnold House School was founded in 1905 by Miss Hanson with nine pupils.

Hanson opened the school with the intention of showing that a headmistress was equally capable of preparing boys for public schools.

By the time she stepped down as Headmistress, the school was flourishing.

The school motto, "Conquer We Shall", is derived from a poem by Robert Herrick: Conquer we shall, but first we must contend, 'Tis not the strife that crowns us, but the end.