The 1981 South African Open was a men's tennis tournament played on outdoor hard courts in Johannesburg, South Africa that was part of the 1981 Volvo Grand Prix. It was the 78th edition of the tournament and was held from 21 November through 28 November 1981. First-seeded Vitas Gerulaitis won the singles title.
Vitas Gerulaitis defeated Jeff Borowiak 6–4, 7–6, 6–1
John Yuill / Terry Moor defeated Fritz Buehning / 
Russell Simpson 6–3, 5–7, 6–4, 6–7, 12–10