Frank Dobbyn, 67, who retired in 1976 as a marketing and development employe of the American Oil Co., died Saturday at his home in Laurel after a heart attack.

He had joined the Petroleum Heat and Power Co. in Stamford, Conn., in 1946 and remained with the firm after it was purchased by the American Oil Co. He worked in the New York region until 1966, when he was transferred to the Baltimore region.

Mr. Dobbyn was born in Wallasey, England. He came to this country at the age of 16 and lived in New York City, where he attended the American Institute of Banking.

During World War II, he served with the U.S. Army Air Corps in Italy.

He is survived by his wife, Lucile Jane, of the home; two sons, Christopher, of Annapolis, and Frank Jr., of Washington; a daughter, Victoria Dobbyn Dill, of Roberts Creek, British Columbia; two brothers, Geoffrey, of Braintree, Mass., and Arthur, of Central Islip, N.Y.; and five sisters, Mary Seems, of Ventura, Calif., Margaret Everett and Josephine Lorenz, both of Harwich Port, Mass., Kathleen Ruysdale, of Hollywood, Calif., and Dorothy Cimilluca, of Nanuet, N.Y.

The family suggests that expressions of sympathy may be in the form of contributions to the Prince George's County Association for Retarded Citizens.