At the outbreak of war, the Regiment was based in India as part of the Ambala Cavalry Brigade and was deployed with the Brigade to France with the 1st Indian Cavalry Division, landing there during November 1914.

In September 1915,  the Brigade transferred to 2nd Indian Cavalry Division, which was renamed a year later as 5th Cavalry Division.

In early 1918, the Division was broken up and, in September of the same year , the Regiment was transferred to 9th Cavalry Brigade, 1st Cavalry Division

The Regiment's Battle Honours include:

Givency, '1914'.

Somme, '1916' '1918'.

Bazentin.

Flers-Courcelotte.

Cambrai, '1917' '1918'.

St Quentin.

Bapaume, '1918'.

Rosieres.

Amiens.

Albert, '1918'.

Hindenburg Line.

St Quentin Canal.

Beaurevoir.

Pursuit to Mons.

France and Flanders, '1914-18'.

124 men from the 8th King's Royal Irish Hussars are listed in the CWGC database of First World War deaths:

1914 - 6.

1915 - 12.

1916 - 10.

1917 - 14.

1918, up 11th Nov - 64.

After 11th Nov 1918 - 18.