Katharine Lee, 76, the principal of the National Cathedral School for Girls from 1950 until 1968, died of cancer Tuesday at the Army Distaff Hall in Washington.

During her years at National Cathedral, Miss Lee guided the school through two major fund-raising drives to expand the physical plant. Proctor Hall was put up in 1956 and Founders Hall in 1960. Both are academic buildings. Scott Hall, an addition to the library, was opened in 1967.

Miss Lee, who had traveled widely in North America and Europe, also conducted student tours to Coventry Cathedral in Coventry, England, during the 1960s.

She was born in San Antonio, Tex. Her father was Army Gen. J. G. C. Lee and her mother was the former Maud Cromlein.

She graduated from Mount Holyoke College, Mount Holyoke, Mass., and then returned to San Antonio, where she taught at St. Mary's Hall School. t

In 1932, she went to New York City.

She taught history and geography at the Chapin School and then at the Brearley School. At the same time, she earned a master's degree at Teacher's College, Columbia University.

In 1940, she went back to San Antonio, this time as headmistress of St. Mary's. From 1945 to 1950, when she moved to National Cathedral, she was principal of Polytechnic Elementary and Junior High School in Pasadena, Calif.

After her retirement from National Cathedral, Miss Lee returned to San Antonio and was a part-time Bible teacher at St. Mary's. In 1970, she became a part-time receptionist at the McNavy Art Institution in San Antonio.

She came back to Washington in 1978 and made her home at the Army Distaff Hall, where she was eligible to live as the unmarried daughter of an Army officer.

She left no immediate survivors.