Old Mother Riley Joins Up is a 1940 British comedy film directed by Maclean Rogers and starring Arthur Lucan, Kitty McShane, Martita Hunt, Bruce Seton and Garry Marsh. It was part of the long-running Old Mother Riley series.
Old Mother Riley works as a nurse before volunteering for the Auxiliary Territorial Service. With the help of her daughter Kitty and Kitty's boyfriend Lieutenant Travers, she thwarts a plan by enemy agents to steal important secret documents.
It was the first Old Mother Riley movie made for British National. Filming took place in August 1939.
TV Guide called the film, "a tolerable romp that kept patriotic English fires burning during the early part of WW II."