What is Sheldon Cooper's twin sister's name?

Sheldon Cooper’s twin sister is Missy. She is introduced as Missy Cooper, the more socially confident and down-to-earth twin who contrasts sharply with Sheldon’s academic brilliance.

Missy first appears in The Big Bang Theory as an attractive, friendly Texan whose arrival immediately fascinates Leonard, Howard, and Raj. Sheldon often treats her as intellectually inferior, but Missy understands people and social situations far better than he does. Their relationship is competitive yet affectionate, and she can often stand up to Sheldon more effectively than his friends can.

The Cooper family’s history is explored further in Young Sheldon. Missy and Sheldon are twins, while their older brother is George “Georgie” Cooper Jr. Their mother is Mary Cooper, and their maternal grandmother, Connie Tucker, is known as Meemaw. Courtney Henggeler played the adult Missy in The Big Bang Theory, while Raegan Revord played her younger version in Young Sheldon.

A common mix-up is confusing Missy with Mary, who is Sheldon’s mother, or Meemaw, who is his grandmother. Missy is the twin sister; Georgie is the older brother.