- Sir William Stephenson
- Sir William Tyrone Guthrie
- Sir William Vallance Whiteway
- Sir William Vaughan
- Sir William Wilfred Sullivan
- Sir William Young
- Sir Willoughby Garnons Gwatkin
- Sirmilik National Park
- Sister Marguerite Jean, S.C.I.M.
- Sister Marie-Stéphane
- Sisterhood of St John the Divine
- Sisters of Providence
- Sisters of St Anne
- Sisters of St Joseph
- Sisters of the Holy Names of Jesus and Mary
