Diller B. Groff II, 80, a retired assistant general counsel of the U.S. Public Housing Administration, died of cancer Feb. 14 at the home of a daughter in Greenville, S.C.

Mr. Groff was secretary to Rep. M. Clyde Kelly (R-Pa.) for 13 years before entering private law practice. He later worked in the office of general counsel of the Government Accounting Office before joining the Public Housing Administration, from which he retired in 1959.

He had been a member of the Washington Board of Trade and the Chevy Chase Citizens Association. A member of Wesley Methodist Church in Washington for more than 50 years, he had served as president of the board of trustees, chairman of the finance committee, and superintendent of the church school.

Mr. Groff was a member of Lafayette Lodge No. 19 of the Masons. He was a Shriner and belonged to Almas Temple.

He was a native of Washington and a graduate of the old Business High School. He earned a law degree at Southeastern University.

Mr. Groff served in the Army during the Mexican border campaign and later in France during World War I.

His wife, the former Carolyn Giles, died in 1967.

He is survived by a son, Dr. Diller B., of Louisville, Ky.; a daughter, Susan C., of Greenville, and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to Wesley Theological Seminary in Washington.