Thomas C. Parry, 50, principal of Thomas Johnson Junior High School in Lanham since 1970, died Wednesday at the Veterans Administration Hospital in Richmond.

He had been under the care of the Medical College of Virginia since undergoing a kidney transplant four years ago but had continued to work actively until shortly before his death.

Born in New Kensington, Pa., Mr. Parry was a graduate of Notre Dame University. He attended Duquesne University in Pittsburgh and received a master's degree from the University of Pittsburgh. He also took graduate work at George Washington University.

He first worked for the Prince George's County public school system as a political science teacher at Bladensburg Junior High School from 1950 to 1953.

Mr. Parry, who had played baseball in the New York Yankees' minor league system, then returned to New Kensington, where he taught political science and coached football, baseball and basketball teams at the high school.

He came back to Prince George's County in 1964 as vice principal of DuVal High School in Lanham, until transferring to Thomas Johnson Junior High School.

Mr. Parry was a member of the Prince George's County Teachers Association, the Maryland State Teachers Association, the National Education Association, the Association of School Administrators and the National Association of Secondary School Principals.

He is survived by his wife, Josephine, of the home in College Park; a brother, John, of Pittsburgh, and a sister, Mary Kantorski, of Arnold, Pa.

The family suggests that expressions of sympathy may be in the form of contributions to the Medical College of Virginia for renal research.