Lexy Gold lives amongst the wealthy and elite of Manhattan, New York. Clad in Prada, she prides herself on her ability to get the scoop and serve it up in her school newspaper's gossip column. She competes for status on the newspaper with Jack Downey, the editor. When a photograph Lexy has taken of her teacher, Mr. Orlando Walker, is published in the city's daily paper, he goes missing and his car is found in the East River. With help from Lexy's best friend Jennifer and one of her schoolmates Gabe, Lexy and Jack set out to solve the mystery behind the disappearance.
Their teacher, Miss Gertrude Dawson, becomes involved as she and Mr. Walker were having an affair. Jack receives a message from Mr. Walker about a scholarship. Lexy and Jack search his old apartment, where they run into Detective Charles Meany, who is searching for Mr. Walker. Jenn and Gabe watch Miss Dawson at Gabe's house with a video camera to keep an eye on her. Lexy and Jack later meet Mrs. Petrossian, who is Mr. Walker's mother, at her house. They discover that Mr. Walker changed his identity after being accused of stealing $10,000,000. Mr. Walker later receives a letter from the real person who stole the money, framing Mr. Walker.
The group and Mr. Walker meet at a hotel to pretend to receive the money. Miss Dawson shows up at the hotel and is taken hostage by the real thief. Lexy and Jack search the halls for the man, who is revealed to be Detective Meany, whose real name is Falco Granville, Mr. Walker's boss when he worked at a bank, and the man who had framed Mr. Walker for the money theft. The team catch up with him and he is later arrested. After Mr. Walker is pronounced a free man at last, he later asks Miss Dawson to marry him.
- Lindsay Lohan – Alexandra "Lexy" Gold
- Bug Hall – Jack Downey
- Ian Gomez – Nicholas Petrossian/Mr. Orlando Walker
- Brenda Song – Jennifer, Lexy's fashion-conscious best friend
- Ali Mukaddam – Gabe, an amateur photographer
- Dan Lett – Frank Gold, Lexy's father, a journalist with the New York Times
- Amanda Plummer – Miss Gertrude Dawson, a teacher
- Charles Shaughnessy – Detective Charles Meany/Falco Grandville
- Kim Roberts – Mrs. Stern
- Eric Fink – Mr. Goldblum
- Jennifer Pisana – Taylor Gold, Lexy's tech-savvy little sister
- Sylvia Lennick – Mrs. Petrossian
- Cheryl MacInnis – Mrs. Sommerville
- Timm Zemanek – Mr. Greenblatt
- Gerry Quigley – Detective Potter
- Keenan MacWilliam – Karen
Production began in May 2001. Get a Clue was written by Alana Sanko and the script was not finished by the time filming had begun. Maggie Greenwald was confirmed to direct and Lindsay Lohan was cast as Lexy Gold, ending her three movie-deal with The Walt Disney Company. The film was primarily filmed in Toronto, Ontario, Canada, with some of the exterior scenes filmed on location in Manhattan, New York. Millington Prep, the school Lexy and her friends attend, was filmed at Bishop Strachan School in Canada.
The film was originally to be released in January 2002 as the Disney Channel Movie of the Month. A well-concealed reshoot took place in late 2001 to film a different ending concluding that the villain in the film was Meany. In the original ending, the villain turned out to be Mrs. Stern, a teacher at Lexy's school who had known Mr. Walker while he was living in Arizona. This ending was shown on the DVD (though the viewer has the option to watch either ending when the movie reaches 61 minutes, with the Mrs. Stern ending shown in a different aspect ratio than the rest of the movie). The teenage detective film was heavily promoted and frequently reaired its initial summer. A song by the band Prozzak, "Get a Clue", appeared in the film and the music video was shown on Disney Channel at the time of its release. The name of the band was changed to "Simon and Milo", the characters depicted in the music video so their band name would not be associated with the drugs. And they refuse to figure out the clues without folowing it.