William W. Fox, 66, a Prince George's County Businessman who was also president of the Landover Hills Volunteer Fire Department, died of cancer Thursday at Providence Hospital.

He was president of the Associated Electric Co. in Seabrook, which he had founded 25 years ago.

Mr. Fox also was president of the Landover Hills fire department, a position he had held intermittently for 20 years. He had helped organize the department in 1945 and had served in every capacity as an administrative officer and as an operations officer up to th: rank of deputy chief.

He was secretary and a past president of the Maryland Fire Chiefs' Association and a past president of the Prince George's County Volunteer Firemen's Association. He also had been secretary of the Maryland State Firemen's Association since 1977.

Mr. Fox was born in Hinton, W. Va. He came to Washington in 1941 and worked as an electrician at the Pentagon. Later he was an electrician with the Electrical Workers Union Local 26 until setting up his own business.

He is survived by his wife, Nettie, of the home in Greenbelt; five children, Richard W., William Joseph, and Elinor Harvey, all of Edgewater, Md., Robert M., of Huntingtown, Md., and Sharon Lawson, of Long Beach, Miss.; a sister, Anna Marie Fox, of Huntington, W. Va., and 12 grandchildren.