Grover W. Penberthy, 55, a career Foreign Service officer with the State Department died Monday at the Cleveland Clinic in Cleveland, Ohio, where he had undergone open heart surgery. He lived in Chevy Chase.

Mr. Penberthy returned two years ago from his last overseas assignment, consul general in Curacao, the Netherlands Antilles. He then held a number of assignments at the State Department here, the most recent being director of systematic review in the Freedom of Information offices.

His earlier overseas assignments included Bonn and Berlin, Germany; Belgrade, Yugoslavia; Monrovia, Liberia, and Belfast, North Ireland.

He was born in Detroit, Mich. and attended Dartmouth College prior to World War II. During the war, he served as a bombardier with the Army's 8th Air Force in Europe. He was awarded the Air Metal.After the war, he remained with the Air Force Reserves, retiring as a lieutenant colonel in 1968.

Mr. Penberthy earned bachelor's and law degrees from the University of Michigan after the war. He was an attorney for the state of Oregon in Salem, served as an assisstant revisor on the Statute Revision Council and executive secretary of the state's Legislative Interim Committee from 1953 to 1955.

He is survived by his wife, the former Janice Marion Green, of Chevy Chase; four children, Betsy Weiland, of Manila, the Philippines, Ward, of Boston, and Martha and Anne, both of Chevy Chase, and two brothers, John M.., of Rochester, Mich., and Phillip E., of Rowayton, Conn.

The family suggests that expressions'' of sympathy be in the form of contributions to the American Diabetes Association.