'Hardihood' was a British unrealised plan to provide aid to Turkey should that country enter the war on the side of the Allies (late 1943).

Schemes of this type had been envisaged by the British as early as 1940, but Turkey had cleverly stayed neutral and received aid from both sides. By 1943 the Allies were providing aircraft, tanks and anti-tank guns, while the entry of Turkey into the war would have been supported by the arrival in southern Turkey from Syria of four infantry divisions and some 18 RAF squadrons. And if the capture of the Dodecanese and other islands in the Aegean Sea could be ensured, further forces could be delivered into Turkey through the port of Izmir.

The definitive plan for 'Hardihood' presupposed a Turkish declaration of war on Germany, which would be followed by a four-phase receipt of Allied reinforcements consisting firstly of three anti-tank regiments and 25 RAF squadrons (mostly fighters) with anti-aircraft defences, secondly of 25 more RAF squadrons with anti-aircraft defences, thirdly of two more anti-tank regiments plus additional anti-aircraft defences in the form of two heavy and two light anti-aircraft regiments, and fourthly two armoured divisions.