Walter Philip Kellenberg (June 3, 1901 – January 11, 1986) was an American clergyman of the Roman Catholic Church. He served as Bishop of Ogdensburg (1954–57) and Bishop of Rockville Centre (1957–76).
Walter Kellenberg was born in the Bronx, New York, to Conrad and Elizabeth (née Kern) Kellenberg. He received his early education at the parochial school of St. Anthony's Church, and attended Fordham Preparatory School and Cathedral College. He made his theological studies at St. Joseph's Seminary in Yonkers. He also took special courses in real estate, insurance, and business administration at Columbia University.
He was ordained to the priesthood on June 2, 1928. His first assignment was as a curate at St. Mary's Church in the Rosebank neighborhood of Staten Island, where he remained for six years. In 1934, he was transferred to St. Paul's Church in New York City and appointed to the archdiocesan curia. Within a year he became a curate at St. Patrick's Cathedral, and was named assistant chancellor and secretary of the Archdiocesan Commission for Real Estate and Insurance in 1939.