G. Allen Sager, 62, principal of Parkdale Senior High School in Riverdale, died Wednesday at his home in Beltsville after a heart attack.

A leading educator and civic worker in this area, he had been principal of the school since it was opened Feb. 1, 1968.

Before that, Dr. Sager had served for four years as vice principal of Northwestern Senior High School in Hyattsville.

Before joining the Prince George's County school system, he had been assistant dean of University College of the University of Maryland for seven years.

Born in Belvidere, Ill., Dr. Sager served as a technical sergeant with the Army's 359th Engineer General Service Regiment in Europe during World War II.

He then earned a bachelor's degree from McKendree College in Lebanon, Ill., and from 1948 to 1950 was a teacher and vocal music instructor in Fort Atkinson, Wis.

Positions as assistant principal at Wisconsin High School in Madison and counselor in the school of education at the University of Wisconsin followed. He earned a master's degree and later a doctorate from the University of Wisconsin.

From 1952 until joining the faculty at the University of Maryland, Dr. Sager was a civilian educational specialist for the Air Force, with assignments in Geneva, N.Y., Tokyo and Hawaii.

He was a member of Phi Delta Kappa educational society, and a past president of its Beta Epsilon chapter at the University of Maryland. He also was a former executive editor of the Marylander, the official publication of University College.

Dr. Sager was a member of the Maryland and National Education associations, the Maryland Association of Secondary School Principals and the American Educational Research Association. He was president of the Prince George's Senior High School Athletic Association.

He was a board member of the Prince George's County chapter of the American Red Cross and cochairman of the Beltsville Interracial Group. He belonged to the American Legion in Greenbelt and the College Park Rotary Club.

Dr. Sager was a counselor for Young Life, a national Christian youth organization. A member of Emmanuel United Methodist Church in Beltsville, he sang in the choir and served on the finance committee. He also sang with the Beltsville Community Chorus.

He is survived by his wife, Esther D., of the home; a son, James Allen, of Columbia, Md., and three brothers, Dr. F. Milton, of Long Beach, Calif.; Richard L. of Columbia Heights, Minn., and Robert W., of Madison.

The family suggests that expressions of sympathy be in the form of contributions to the Dr. G. Allen Sager Memorial Scholarship Fund at Parkdale High School.