Stanley Howard Knowles, PC OC (June 18, 1908 – June 9, 1997) was a Canadian parliamentarian. Knowles represented the riding of Winnipeg North Centre from 1942 to 1958 on behalf of the Co-operative Commonwealth Federation (CCF) and again from 1962 to 1984 representing the CCF's successor, the New Democratic Party (NDP).Knowles was widely regarded and respected as the foremost expert on parliamentary procedure in Canada, and served as the CCF and NDP House Leader for decades.