Delia (Dee) Benavides, 15, a native of Lima, Peru, and a ninth grade student at Tilden Junior High School in Rockville, died Saturday at the Children's Hospital National Medical Center in Washington. She had suffered from muscular dystrophy since birth.

The daughter of a Peruvian diplomat, Delia moved to Rockville with her family in 1975. Confined to a wheelchair, she attended the wing for orthopedically handicapped students at E. Brooke Lee Junior High School in Silver Spring before transferring to Tilden last year, where she participated in regular classes. A younger sister, Ana Maria, who was also afflicted with muscular dystrophy, attended Lee before her death three years ago.

Last year an article on handicapped programs in a Montgomery County school community newsletter focused on Delia's determination to attend a regular neighborhood school instead of a special school or institution.

The article related the problems Delia had faced at Lee Junior High, including her distress when listed under "Orthopedically Handicapped" rather than by her grade level on the honor roll at Lee.

Despite her handicap, Delia attended summer camps and participated in other teen-age activities. Last year, she was a panelist in a program at Gallaudet College in preparation for the International Year of the Disabled, 1981.

Survivors include her parents, Nestor and Delia Benavides and a brother, Nestor Miguel, all of Rockville.

The family suggests that expressions of sympathy be in the form of contributions to the Peruvian Rehabilitation Institute.