HMCS Middlesex was a reciprocating engine-powered Algerine-class minesweeper built for the Royal Canadian Navy during the Second World War.

The engines produced a total of 2,400 indicated horsepower (1,800 kW) and gave a maximum speed of 16.5 knots (30.6 km/h; 19.0 mph).

They carried a maximum of 660 long tons (671 t) of fuel oil that gave them a range of 5,000 nautical miles (9,300 km; 5,800 mi) at 10 knots (19 km/h; 12 mph).

Many Canadian ships omitted their sweeping gear in exchange for a 24-barrel Hedgehog spigot mortar and a stowage capacity for 90+ depth charges.

In April, Middlesex rescued 32 crew and passengers from the merchant vessel Alfios after the ship had run aground on Sable Island.

[5] While responding to an emergency call from the fishing vessel Ohio in December, Middlesex ran aground on Half Island Point near Halifax.