According to one of the featurettes on the DVD, several of the shots in the movie were added after initial filming ended. These included the scenes of Rudy and Tripper at the bus station and of them playing blackjack for peanuts. During the time off, Chris Makepeace had entered puberty and had the beginnings of a mustache. Bill Murray decided that it had to go so he took Makepeace over to a sink, lathered him up with soap and shaved off his mustache. So Makepeace received his first ever shave from Murray.
The movie was filmed at an actual summer camp, Camp White Pine, in Haliburton, Ontario (a few hours north of Toronto). Many of the extras in the film were actual campers and counselors of the camp; most if not all locations were actual camp facilities (basketball courts, mess hall, swim docks, cabins, etc.). The "Visitors Day" scene/montage was actually filmed during the camp's Visitors Day; White Pine also had a similar yearly event to the "Olympiad" - although rather than being a inter-camp competition, it was an intra-camp relay-type competition that was just part of an overall all-day themed event. These competitions were nicknamed "Mohawk Relays", perhaps serving as inspiration for the name of the rival camp in the movie.
Wikipedia states, "Harold Ramis said that [Ivan] Reitman did not know for certain whether [Bill] Murray would be in the movie until he showed up for the first day of filming". According to Brett Martin's July 2009 article "Harold Ramis Gets the Last Laugh" published in GQ, "Bill left Ivan hanging . . . Ivan didn't know if he was going to be there until the day they started shooting".
Camp North Star was portrayed by real life Camp White Pine. During principal photography, the camp was a fully operational and functioning facility and was not closed down during the shoot. Similarly, Camp Mohawk was portrayed by real life Camp Towhee. Both camps are located in Haliburton in the province of Ontario in Canada.
One of a number of hit comedies with one word titles for actor-comedian Bill Murray which were made and released during his early period of feature film work. The pictures include Stripes (1981), Tootsie (1982), Meatballs (1979), Caddyshack (1980) and Ghostbusters (1984) (aka Ghostbusters).
Some movie posters for Meatballs featured this lengthy tagline: "The Summer Camp That Makes You Untrustworthy, Disloyal, Unhelpful, Unfriendly, Discourteous, Unkind, Disobedient, and Very Hilarious". (This is a reverse of much of the "Scout Law" from the Boy Scouts of America: "A Scout is Trustworthy, Loyal, Helpful, Courteous, Kind, Obedient, Cheerful, Thrifty, Brave, Clean, and Reverent.")