The most famous line from the film, "Love means never having to say you're sorry", was actually misspoken from the script. Originally the line was supposed to be: "Love means not ever having to say you're sorry."
The scenes with Oliver walking alone through a snowy New York were added after principal photography was completed. The production was almost out of money and did not have the necessary funds for permits to shoot in New York City again - so all the shots were grabbed "illegally" using a skeleton film crew and Ryan O'Neal.
John Wayne refused to believe that Love Story (1970) "sold because the girl went around saying 'shit' all the way through it." Instead he believed that "the American public wanted to see a little romantic story."
Both the Cornell and Dartmouth hockey teams were played by Dartmouth's actual team. Cornell hockey coach Ned Harkness only allowed Cornell jerseys to be used in the film on the condition that Cornell win the game with Harvard.