- Acting for Two: In The Movie, Isabella Parigi is portrayed by Hilary Duff, but some sources say Haylie Duff (Hilary's sister) provided the singing voice.
- Actor Allusion: One is made with David and Robert Carradine in the episode where Gordo and Matt make a kung fu movie.
- Actor-Shared Background: Adam Lamberg is Jewish like his character.
- Dawson Casting:
Animated Lizzie: Wow, Miranda's officially in love with acting. Maybe when she's thirty years old, she can play a teenager on Dawson's Creek.
- 17-year old Adam Lamberg as Gordo; because he hit puberty late, he is actually able to pass as a 12-year old pretty convincingly in the pilot, and he managed to remain shorter than Lizzie and Miranda all the way through to the end.
- 18-year old Kyle Downes as middle schooler Larry Tudgeman. Made more Egregious by the fact that, in the previous series he was in (the Retroactive Recognition-palooza Higher Ground), he was cast as a troubled high schooler.
- Also comes up in Conversational Troping when Miranda acts in a school play:
- Defictionalization: In one episode, Lizzie was inspired to spend more time with her mother after reading a novel titled The Orchids and Gumbo Poker Club for a school assignment. Disney later published an actual novel with that title, with notes from Lizzie included in the margins.
- Fake Nationality:
- He Also Did: Elliot Lurie, who composed the show's theme song, was previously lead vocalist and guitarist for the Looking Glass, an early '70s pop rock band from New Jersey best known for their number one song, "Brandy (You're a Fine Girl)".
- The Merch: Fortune magazine estimated in 2003 that Lizzie McGuire merchandise had earned the Walt Disney Co. nearly $100 million! That's from Radio Disney's big CD promotion, books based on the episodes being sold, mystery books starring Lizzie (much in the same vein as the Mary-Kate and Ashley Olsen mystery books), Tokyo POP manga adaptations, bed sheets, Barbie dolls, board games, and The Movie.
- Reality Subtext: Aaron Carter guest stars As Himself and shares a kiss with Lizzie under the mistletoe. Carter dated Hilary Duff for a while.
- Technology Marches On:
- In an earlier episode, Matt and Lanny try to raise the money to buy ninety-dollar walkie-talkies. A floppy disk and a VHS tape make appearances in the same episode.
- Throughout the series, Lizzie, Miranda, and Gordo have landlines in their bedrooms rather than cell phones.
- In Rumors, Lizzie and Miranda are chatting on a fake ICQ client while using Windows 98!
- In "Lizzie and Kate's Big Adventure", Lizzie and Kate have to go to an Internet café in order to get DSL.
- What Could Have Been:
- They seemed to be building up to a romance between Larry and Miranda before the latter left the show. The storyline where he hooks up with a minor recurring character was most likely originally for her.
- There were plans to spin off a "Lizzie in high school" sitcom onto ABC, but never got to be produced, due to Hilary Duff leaving after the show's completion.
- A pilot for an unaired spinoff series called "What's Stevie Thinking?" was allegedly shot (or at least written), concerning the adventures of Miranda's sister Stevie. Stevie was to be played by a very young Selena Gomez.
- Towards the show's end, there was a contest for three girls to have animated versions of themselves to have a cameo with the animated Lizzie. The show ended before this could have happened.
- Sara Paxton was the front runner to play Lizzie before Hilary Duff was cast. She later appeared in the episode "Election".
- Ethan Craft was originally written to be the school bully. He was changed to a heartthrob and any of his bully qualities were given to Kate.
- After the 9/11 terrorist attack, the clocks in Lizzie's school are set at 9:11 for the episode directly after it.