Mary Ellen Wallace, 92, an elementary school teacher in Prince George's County for 44 years before her retirement in 1954, died of pneumonia Wednesday at Howard University Hospital.

Miss Wallaces entire teaching career was spent in Prince George's County. Her last assignment was at the old Sojourner Truth School in Oxon Hill.

She was born in Queen Anne's County on Maryland's Eastern Shore. She attended the Hampton Institute in Virginia, Morgan State College in Baltimore, Columbia University in New York City and Howard University and Catholic University in Washington.

Miss Wallace, who lived in Washington, devoted much of her time to church work. She was active in the Reid Temple A.M.E. Church here, where she had served as a stewardess, Sunday school teacher and superintendent, and as treasurer and president of the Missionary Society.

In 1978, she was honored by the church for her contributions in Senior Citizens Night ceremonies which included words of praise from President Jimmy Carter, D.C. Mayor Marion Barry and D.C. Del. Walter E. Fauntroy.

She also was honored by the Washington area Federation of Women's Clubs in 1974 and 1978.

Miss Wallace was a member of the United Church Women, the Maryland Retired Teachers Association, the Anacostia Historical Society, the Mary A. Campbell Circle and other service organizations.

Survivors include two sisters, Henrietta C. Rowe, of the home in Washington, and Bernice W. Matthew, of Riverdale, N.Y.

The family suggests that expressions of sympathy be in the form of contributions to the Reid Temple A.M.E. Church building fund.