Anthony Michael Hall and Molly Ringwald initially disliked each other, so John Hughes took them to a record store and they bonded after they found out they like the same music. One of the groups they liked was The Rave-Ups which Molly scribbled on Samantha's notebook.
The movie's costume designer begged Molly Ringwald not to wear the hat she wore in the beginning of the movie. Ringwald insisted. After the movie was released, teenage girls started wearing their hats tilted back like that.
Of all the films Molly Ringwald made with John Hughes, she said, "I had the most fun on Sixteen Candles."
Viggo Mortensen auditioned for the role of Jake Ryan. Molly Ringwald told Access Hollywood: "I really wanted him. He made me weak in the knees. He really did."
Haviland Morris didn't want to do the shower scene, because the point was that she had bigger breasts than Sam and Randy, which she didn't. So they had a body double for her.
Dick Biondi: Chicago radio legend is heard on the radio (uncredited) in the opening bedroom scene where Molly Ringwald is looking in her mirror.