Dove Cameron was initially cast for a single role on the series, which originally was not to center around her. When the show was first developed it was to be about a mixed/step family learning to come together, similar to La famiglia Brady (1969) or Una bionda per papà (1991). Most of the cast for the original concept was retained, with changes made to the names of some characters.
In real life, Dove Cameron (Liv & Maddie) and Joey Bragg (Joey) were born the same year, Cameron being 6 months older than Bragg.
Parker in one of the episodes watches a show called "Linda and Heather", which is actually named after producers Linda Mathious and Heather MacGillvray. They're played by Emmy Mattingly and Shelby Wulfert, who are the body doubles for the twins credited as "Liv 2" and "Maddie 2" in every episode.
First Live Action Disney Channel Show to have a Season set after High School Graduation for the Main Characters. When the Season 3 Finale was filmed, the Producers didn't know if the show was getting picked up for a 4th Season seeing as the 3rd Season had been set in the Title Characters' Senior School Year (Disney Channel shows usually have wrapped up after then), and filmed it in a way to wrap up the series.
Jessica Marie Garcia is 10-11 years older than her Character Willow Cruz, being one of the oldest cast members in the series.