The Boondock Saints II: All Saints Day is a 2009 American vigilante action thriller film written and directed by Troy Duffy, based on a story by Duffy and his brother Taylor. A sequel to The Boondock Saints (1999), the film stars Sean Patrick Flanery, Norman Reedus, Clifton Collins Jr., Julie Benz, Peter Fonda, and Billy Connolly. Set eight years after the events of the first film, it follows Irish fraternal twin brothers Connor and Murphy MacManus (Flanery and Reedus) living a quiet life in Ireland with their father Noah, formerly known as "Il Duce" (Connolly). However, when an assassin frames the twins for the murder of a Catholic priest, they return to Boston and join forces with Mexican underground fighter Romeo (Collins, Jr.) and FBI Special Agent Eunice Bloom (Benz), a former protégée of Paul Smecker.

The Boondock Saints II: All Saints Day had its world premiere in Boston on October 19, 2009, and was theatrically released in the United States on December 11, 2009. Despite negative reviews from critics, the film was a modest success at the box office, grossing $10.6 million against its $8 million budget. A sequel is currently in development, with Duffy, Flanery, and Reedus expected to return.