HMCS Orkney was a River-class frigate that served with the Royal Canadian Navy as a convoy escort during the Second World War.

[5] The name "frigate" was suggested by Vice-Admiral Percy Nelles of the Royal Canadian Navy and was adopted later that year.

[5] 15 Canadian frigates were initially fitted with a single 4-inch gun forward but with the exception of HMCS Valleyfield, they were all eventually upgraded to the double mount.

[6] For underwater targets, the River-class frigate was equipped with a Hedgehog anti-submarine mortar and depth charge rails aft and four side-mounted throwers.

[5] River-class frigates were the first Royal Canadian Navy warships to carry the 147B Sword horizontal fan echo sonar transmitter in addition to the irregular ASDIC.

[3] She served with the unit until 13 February 1945 when she was involved in a collision with the merchant ship SS Blairnevis in the Irish Sea.

[4] Orkney suffered severe damage, requiring her grounding to keep her afloat, while Blairnevis sank as a result of the collision.

She was worked up at Tobermory before returning to Canada in late May 1945 to undergo a tropicalization refit at Louisburg, Nova Scotia in preparation for service in the southern Pacific Ocean.