Old Bill and Son is a 1941 British black-and-white comedy war film directed by Ian Dalrymple. Centred on the First World War cartoon figure Old Bill and his escapades in the early Phoney War of World War II and with that character's creator Bruce Bairnsfather as one of its screenwriters, it stars Morland Graham, John Mills, Mary Clare and Ronald Shiner as Herbert 'Bert' Smith. It is executive produced by Alexander Korda for Legeran Films.

Old Bill is a fictional character created in 1914–15 by cartoonist Bruce Bairnsfather. Old Bill was depicted as an elderly, pipe-smoking British "tommy" with a walrus moustache. The character achieved a great deal of popularity during World War I where it was considered a major morale booster for the British troops. Old Bill and his younger troopmate little Alphie were private infantrymen in the British Expeditionary Force.