The Boondock Saints

The church where Connor (Sean Patrick Flanery) and Murphy (Norman Reedus) attend Mass, Church of the Covenant, is not a Catholic church, but a Lutheran one. No Catholic churches in the area would allow filming in their sanctuaries due to their objections to the plot of this movie.

Rosengurtle Baumgartner is wrong about what "rule of thumb" means. In reality "rule of thumb" is a medieval term referring to an ordinary, everyday measurement system. The idea that "rule of thumb" condones spousal abuse is believed by many people, but isn't true. The "wife beater's rule of thumb" was invented in 1782 by a humorist, James Gillray, as a metaphor to satirize incompetent legal systems. Many people mistakenly believed (and still do) that he was referring to an existing law.

Clips of people being interviewed about their opinions on "the saints" are shown while the credits roll.

The so-called North American widescreen DVD release is cropped from a full-frame version that has aired on Canadian cable television.

Edited into The Boondock Saints II: All Saints Day (2009)