GLAAD says the cable network gets an "excellent" rating for having a lot of gay and lesbian characters and for the way they fit naturally into the shows.
The group cites "Pretty Little Liars" for having a lesbian character.
GLAAD also gives credit to "The Secret Life of the American Teenager" for having several gay and lesbian characters.
ABC Family says its young audience expects the nation's diversity to be reflected in its programming.
ABC Family, the top-rated cable network among viewers ages 12 to 34 and particularly strong among girls and young women, was cited for both a large number of gay and lesbian characters and the way those characters fit naturally into the shows.
The only other network judged "excellent" by GLAAD was MTV last year.
The Associated Press contributed to this report.