Margaret Wilson Stack, 72, a former teacher and an active participant in civic affairs in Montgomery County, died Friday of myelofibrosis at her home in Silver Spring.

Born in Ottawa, Ontario, she grew up in Westmount, Montreal. She was a graduate of MacDonald College of McGill University.

Mrs. Stack had lived in Montgomery County since 1932. From 1955 to 1968, she taught kindergarten at Forest Grove and Highland Elementary Schools. During that period, she attended the University of Maryland, graduating from its College of Education in 1964.

Active in PTA work at local, county and state levels, Mrs. Stack also had served on the Montgomery County Library Board.

She was a member of the Silver Spring Women's Club and had served on a number of boards and committees of Foundry United Methodist Church.

She is survived by her husband, Arthur, of the home; a son, Arthur J., of La Canada, Calif; two daughters, Sandra Cartwright-Brown, of Chevy Chase, and Melinda Staley, of Gaithersburg; a sister, Evelyn Bennett, of Kanata, Ontario; a brother, Charles Wilson, of Winnipeg, Manitoba, and six grandchildren.

The family suggests that expressions of sympathy may be in the form of contributions to a memorial fund in her name at Foundry Chruch or the Leukemia Society of America.