Starlight Glimmer is a female unicorn pony and recurring character, initially an antagonist, in the series. She first possibly appears in My Little Pony: Friends Forever Issue #14 and first explicitly appears in the season five premiere. From The Cutie Re-Mark - Part 2 to Celestial Advice, she is Twilight Sparkle's student in the ways of friendship.
- She is the first villain in a two-parter to be, or at least have the appearance of, a regular pony. Nightmare Moon was an alicorn with an ethereal mane, Discord was a draconequus, Queen Chrysalis was a changeling with the appearance of an insectoid alicorn, King Sombra was a demonic unicorn with a shadow form, Lord Tirek was a centaur and The Dazzlings were sirens. The only other villain who is a regular unicorn is Sunset Shimmer, who appeared in a movie and is mostly seen in human form. Even then, Sunset had a demonic empowered form, while Starlight did not.
- Starlight Glimmer will become Thomas, Ash and Mickey's enemy in Thomas' Adventures of My Little Pony Friendship is Magic - The Cutie Map, but will reformed in Thomas' Adventures of My Little Pony: Friendship is Magic - The Cutie Re-Mark and joins the team at the end of the film.
- Starlight Glimmer will make a cameo appearance in the Post Credits Scene in Team Robot in Pokémon the Movie: Hoopa and the Clash of Ages and will be guest staring in Team Robot's Misadventures Of Thomas & Friends: Tale of the Brave.
- The voice of Kelly Sheridan as Starlight Glimmer shares with her favorite characters by Megan Williams and Barbie Roberts.
- Starlight Glimmer has a boyfriend named Mirage.
- During Pooh's Adventures of Cars, Starlight Glimmer formed a special friendly brotherly and sisterly relationship with Lightning McQueen.
- The TARDIS Team will befriend her in Doctor Aaron's Mirror Magic Montage.