David Hugh "Taffy" Williams (28 September 1933 – 7 May 1996) was a Welsh-born South African mercenary who fought for the State of Katanga during the Congo Crisis (1960–1963) and the Republic of Biafra during the Nigerian Civil War (1967–1970).

Noted for his bravery under fire he served two tours of duty with the Biafran Army, rising to the rank of major, and was the last white mercenary to leave the country as secession ended.

[3] Williams was known in Biafra as being "bullet proof" due to his ability to survive multiple wounds and was five times reported to be killed in action between December 1967-October 1968, only for him to turn up alive.

[3] Williams was assigned one hundred Biafran fighters in early 1968, and managed to keep two battalions of Chadian mercenaries serving with the Nigerian Federal Army at bay for twelve weeks with only antiquated weapons.

After Williams redeployed his forces in early April, the Chadians forded the Cross River at two locations, and captured Afikpo, a main town on the western side.