The Best Little Girl in the World is a 1979 American young adult coming of age novel by Steven Levenkron, telling the story of Kessa, a teen who suffers from an eating disorder.

Fixated with weight loss and treated like a young child by her family, Kessa retreats further and further into her mental illness, leading her parents to finally recognize it months later, after which they send her to a male therapist.

Kessa develops romantic feelings for the therapist, which would cross ethical boundaries if acted upon, and she also deals with the death of a friend in the hospital.

As she gradually recovers, various ideas for what caused the eating disorder are explored at length: Kessa loathes her emerging womanhood and puberty as it affects her contours, including her breasts, waist and buttocks.

The Best Little Girl in the World was in part based on Levenkron's experiences with deceased musician Karen Carpenter, who later died in 1983 after a long struggle with an eating disorder.