Major General Sir Henry Fleetwood Thuillier, KCB, CMG (30 March 1868 – 11 June 1953) was a British Army officer who played a significant part in the development of gas warfare.

Thuillier was born at Meerut, Uttar Pradesh, India, on 30 March 1868, the son of Colonel Sir Henry Ravenshaw Thuillier.

[1] He became commander of 2nd Infantry Brigade in October 1915, General Officer Commanding 15th (Scottish) Division in June 1917, after receiving a temporary promotion to major general,[3] and General Officer Commanding 23rd Division in Italy in 1918, during the First World War.

[4] After the war Thuillier, promoted in June 1919 to substantive major general,[5] became Commandant of the School of Military Engineering in November 1919, Director of Fortifications and Works at the War Office in 1924,[6] and General Officer Commanding 52nd (Lowland) Infantry Division in June 1927.

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