Rudolph Lambart, 10th Earl of Cavan

Field Marshal Frederick Rudolph Lambart, 10th Earl of Cavan (16 October 1865 – 28 August 1946), known as Viscount Kilcoursie from 1887 until 1900, was a British Army officer who served as chief of the imperial general staff (CIGS), the professional head of the British Army, in the 1920s.

After being commissioned into the Grenadier Guards in 1885, he served in the Second Boer War as a company commander, then served with distinction during the First World War as a brigade, divisional, corps, and army commander, and later advised the British government on the implementation of the Geddes report, which advocated a large reduction in defence expenditure; he presided over a major reduction in the size of the British Army.