[3] The regiment was part of the Northern Force sent to invade (the then) German South-West Africa at the outbreak World War I.

The unit was renumbered as the 3rd Citizen Battery (THA) in 1926, and reverted to the name Transvaal Horse Artillery in 1932.

The regiment's most memorable action during the war was during the battle of Sidi Rezegh in the Western Desert on 23 November 1941.

As a part of 5 South African Infantry Brigade Group, the THA suffered considerable losses during heavy action which saw it firing over open sights at the panzers of the Afrika Korps.

It subsequently joined 4/22nd Field Regiment, South African Artillery and saw action throughout the Italian Campaign.

[2] Other operations included: In August 2019, 52 Reserve Force units had their names changed to reflect the diverse military history of South Africa.

[8][2] On 11 June 2007 the THA shared a Royal Salute alongside the Honourable Artillery Company, (HAC) at the traditional saluting base, the Tower of London, in honour of the official birthday of Prince Philip, Duke of Edinburgh, consort to Queen Elizabeth II.