It is stated in many episodes that Miranda and her family are from Mexico and they follow all its cultures and holidays. The Halloween episode shows her family celebrating The Day of the Dead. She also knows some Spanish when the gang attempt to go on a Spanish game show, but not enough to be very helpful.
She is shown babysitting a baby sister in one episode; this is the only sibling she is portrayed as having in the series, but a planned spin-off for which a pilot episode was filmed but never aired featured Miranda's sister, Stevie Sanchez, as the title character and made her just a few years younger than Miranda.
Near the end of the series, Miranda appeared less in the show, although she appeared in the final episode. She was, however, absent from The Lizzie McGuire Movie, which went to movie theaters in 2003.
- In 4th Grade, Miranda snacked on dog biscuits.
- Miranda is of Mexican heritage in comparison to the Filipino Lalaine in reality.
- It is revealed in "Misadventures in Babysitting" that she has a baby sister, but her infant sister was never seen in the series.
- Her parents are Edward and Daniella Sanchez, and she has a sister, Stevie, as revealed later when Disney announced the spin-off show about her sister, What's Stevie Thinking, starring Selena Gomez as Stevie (though the show never aired).
- Miranda is smart and witty and sometimes doesn't get along with Gordo. She and Lizzie were friends with Kate for a while, but Kate gained popularity and became their nemesis.
- Matt had a crush on her in the episode, "Working Girl".
- She was born on December 15, 1989.