Anna-Kat Millie Tristan Otto is the third and youngest child and littlest and second daughter of Katie and Greg and the younger sister of Taylor and Oliver. She is 11 years old and is played by Julia Butters. She is 13 year old and it will portrayed by Giselle Eisenberg.
Anna-Kat was born in 2009 making her the youngest. The Ottos moved to Westport for better schools for Anna-Kat.
Anna-Kat has obsessive-compulsive disorder (OCD), which makes her act different than other kids her age. Anna-Kat washes her hands multiple times, is afraid of germs, pees in the yard, walks up the stairs in some sort of pattern, and more. She is much more obedient then her older siblings as in Back to School when Anna-Kat is the only one to listen to Katie's instructions.
- She has obsessive-compulsive disorder (OCD).
- She has a fear of natural disasters.
- She is Katie's favorite child.
- She is a germophobe.
- She enjoys playing with her ponies.
- She has trouble making friends.
- She doesn't like it when Oliver or Taylor are unhappy.
- Her best friend is Franklin.
- “I’m getting great at peeing outside.”
- “Stop breathing your germs, I’m completely defenseless!”
- “I just don‘t feel like it today.”
- "No wonder your husband left you."
- “Someone stole my ponies!”
- “You took my glue stick, you made it my business."
- “I did.”
- “Don’t play me, you know it’s cute.”
- “She gave me raisins for my birthday! In a baggy!”
- “I’m not Google, Franklin.”
- “Don’t you have a heart?”
- "Oh, Franklin, just when I think you're going to zig, you zag!"