The scene where Andrea Martin playfully grabs John Corbett's hair was ad-libbed; Martin had forgotten her lines, played with Corbett's hair (to which Corbett stayed in character and played along), remembered her lines and continued. Nia Vardalos said that it worked out so well they decided to print the take and use it.
Tom Hanks's wife, Rita Wilson, saw the play and recommended that her husband produce a movie version. In an interview with the German magazine "Cinema", Nia Vardalos mentioned that she hung up when Hanks called, because she didn't believe it was really him.
The opening scene where Nia Vardalos and Michael Constantine travel in the early morning to open the restaurant was one of the very last scenes filled. Vardalos said that all of the other cast members had finished their scenes and had left, and so the sadness she and Constantine had in that car scene reflected the tearful goodbyes they'd said.
When Andrea Martin's character learns that John Corbett's character is a vegetarian, she gets a bewildered look and replies, "That's okay. I make lamb." Nia Vardalos said this reflects the confusion that many Greeks have toward vegetarianism. During World War II, food was scarce, so Greeks subsisted on anything available. To them, it makes little sense not to eat meat.
According to Nia Vardalos, paying for catering during the film proved not to be a problem. Wherever the film was being shot, whenever local Greek restaurants learned about it, they sent over lots of free food.
Despite its status as a small independent film, and despite never holding the number one spot at the American box office, the movie went on to earn almost US$369 million, a return of over sixty-one times (6150%) its US$6 million (inflation-adjusted) budget. For that reason, it is the second most profitable film of all time after Paranormal Activity (2007). That film returned 12890 times the money invested (1289038.67%) with a budget of $15000. The Worlwide Box Office stopped ringing in $193m.
Originally developed by Nia Vardalos as a one-woman stage show. The film had a special sneak preview at the Montreal Just For Laughs's Comedy film festival in July 2001, as she was performing in the same city.
In the fall of 2002 the film surpassed Dances with Wolves (1990) as the highest grossing movie never to have hit number one at the weekend box office. By the weekend of October 4-6, it surpassed The Blair Witch Project (1999) as the highest-grossing independent film of all time, until March 2004, when it was surpassed by The Passion of the Christ (2004). Theatres continued to run the film after its initial video release.
Nia Vardalos is a Ryerson University graduate. The university was used for several scenes in the film. Kerr Hall is the school where Ian Miller teaches. The Rogers Communications building plays Harry S. Truman College.