Sir Arnold Theiler KCMG (26 March 1867 – 24 July 1936)[1] Pour le Mérite[1] is considered to be the father of veterinary science in South Africa.

In 1891, Theiler travelled to South Africa and at first found employment as a farm worker on Irene Estates near Pretoria, owned by Nellmapius, but later that year started practising as a veterinarian.

His success at producing a vaccine to combat an outbreak of smallpox among the miners of the Witwatersrand brought him an appointment as state veterinarian for the Zuid-Afrikaansche Republiek, in which capacity he served during the Anglo-Boer War of 1899–1902.

The University of Pretoria Faculty of Veterinary Science was established there in 1920 which enabled veterinarians to train locally for the first time.

He married Emma Sophie Jegge (1861–1951) and had two sons and two daughters, the younger two of whom worked at Onderstepoort: Hans (1894–1947), a veterinarian; Margaret (1896–1988), a teacher; Gertrud (1897–1986), a parasitologist and professor; and Max Theiler (1899–1972), a Nobel laureate in 1951 in Physiology and Medicine.