- Orchestras Canada/Orchestres Canada
- Orchestras
- Orchestre des jeunes du Québec
- Orchestre Métropolitain
- Orchestre Métropolitain du Grand Montréal
- Orchestre Métropolitain
- Orchestre sympathique
- Orchestre symphonique de Montréal / Montreal Symphony Orchestra
- Orchestre symphonique de Québec
- Orchid
- Order-in-Council
- Order-in-Council PC 1911-1324, 12 August 1911
- Order-in-Council P.C. 1911-1324 — the Proposed Ban on Black Immigration to Canada
- Order of British Columbia
- Order of Canada
