Princess Celestia (voiced by Nicole Oliver) is the beautiful alicorn co-ruler of Equestria along with her younger sister Princess Luna in My Little Pony: Friendship is Magic. They're both responsible for raising the sun, moon and stars. She is the mentor to Twilight Sparkle and addresses her as "My faithful student". Although considered a wise ruler, she's also fun loving and impish, but never does anything that can harm her subjects. Although she is kindhearted and slow to anger, Celestia's patience does have its limits. An example is towards Discord and Tirek.
In the Jaden's Adventures series, the Jeffrey & Friends' Adventures series and the Hiccup's Adventures series, she is a mentor to Jaden, Jeffrey and Hiccup, knowing that they are very kind, brave, loyal and strong. She also considers them to be her faithful students, just like Twilight Sparkle.
- Princess Celestia will guest star in Jeffrey & Friends meet Bambi.
- Princess Celestia will guest star in Jeffrey & Friends' Storm Adventures of Don't Eat the Pictures. She'll help Osiris put Prince Sahu though a test.
- Princess Celestia will guest star in Jeffrey, Jaden & Friends' Storm Adventures of Rise of the Guardians. It'll be revealed that she's a Guardian,just like North, Sandy, Tooth and Bunnymund. She is The Guardian of Harmony.
- Princess Celestia will guest star in Pooh, Jaden, Jeffrey & Friends' Storm Adventures of The Muppet Show Episode 217: Julie Andrews.
- Princess Celestia will guest star in Jeffrey and Jaden's Duel.
- Princess Celestia will guest star in Jeffrey, Jaden & Friends' Storm Adventures of Scooby Doo 2: Monsters Unleashed.
- In Xion's Keyblade Training, Princess Celestia will personally oversee Xion's training.
- Princess Celestia will appear near the end of Jeffrey, Jaden & Friends meet The Brave Little Toaster.
- Princess Celestia will attend Jeffrey and Aqua's wedding in Key of Flaming Union.
- Princess Celestia will guest star again in Jeffrey, Jaden, Hiccup and Friends' Storm Adventures of Disney's Believe.
- Princess Celestia will attend Jesse and May's wedding in Rainbow Bond.
- Princess Celestia serves as a Summon for Mitsuki.
- Princess Celestia is aware of Ralphie becoming a good guy. Like Rapunzel and the Ohanas, she believes that he can be reformed.
- In the Thunderbolts Adventure Series, Princess Celestia is Courtney's biological mother and used to be good friends with Steven's mother; Rose Quartz. Solgaleo also has a mysterious connection with her.