On January 8, 1902, Philip Primrose married Lily Deane (June 3, 1877 – March 15, 1966). She was the daughter of Superintendent Richard Burton Deane of the North-West Mounted Police. Deane had served with the NWMP during the Riel Rebellion of 1885, tasked with guarding Riel and 50 other participants of the uprising in their prison cells. The Primroses had four children: Phyllis Jessie (1902–1975), Neil (1904–1904), Neil Philip (1905–1991), and Sybil E. (c. 1909–1946). His oldest son, Neil Philip was a lawyer, practicing in Vegreville and Edmonton. After being created a King's Counsel in 1951, Neil served as a Judge with the Supreme Court of Alberta in its Trial Division. One of his grandchildren, John Nairn Primrose won trap shooting championships at the Commonwealth Games in 1974 and 1978 respectively, as well as going on to win two world championships, and, in 1981, was appointed as a member of the Order of Canada.