Mathilde D. Williams, 84, a former employe of the D.C. Public Library system and a retired curator of the Peabody Library Association of Georgetown, died Friday at Sibley Memorial Hospital following a stroke.

Miss Williams was a lifelong resident of Washington. She earned bachelor's and master's degrees in history at George Washington University.

She began with the public library in 1918 and served as a cataloguer, reference librarian, branch librarian and editor. She retired in 1949.

In 1950, she became curator of the Peabody Library Association at the Georgetown branch of the public library. The association is devoted to the history of Georgetown, and Miss Williams remained with it until her retirement in 1978.

Miss Williams was a member of the board of managers and of the advisory committee on historical research of the Columbia Historical Society. She contributed frequently to the society records.

She also was a member of the Zonta Club of D.C., a service organization for professional women, and for 25 years was editor of The Zontagram, the group's publication.

She had been secretary of the Forest Hills Citizens Association and was a member of the Altar Guild of St. Columba's Church in Washington.

There are no immediate survivors.