Trivia

In filming the shot in which Doug #1 introduces Doug #3 to Doug #2, Doug #2 tosses a beer to Doug #1. Michael Keaton catching the beer (tossed by a body double) was shot first. Keaton tossing the beer (this time *to* a body double) was filmed later. Keaton's toss so perfectly matched the body double's original toss that the planned special effect of digitally erasing the tossed beer can then adding in a digital beer can was not needed, thereby saving the production quite a bit of money. This was referred to by the special effects crew as "The Million Dollar Miracle Beer Can Toss".

According to director Harold Ramis, he wrote much of the script uncredited. A Writers Guild rule prevents directors from getting a writing credit on their film unless they contribute more than fifty percent. Ramis contributed forty percent of the screenplay.

Michael Keaton doesn't wear a wedding ring throughout the whole movie to prevent continuity errors.

The construction project Doug is working on is called "Vista de Nada," which is Spanish for "View of Nothing".

Doug Kinney was named after Ramis' friend and National Lampoon founder Douglas Kenney.