Anger over corruption, the faltering economy and land reform are key issues as South Africans vote in the sixth democratic nationwide election since apartheid ended 25 years ago.
The African National Congress (ANC), which led the fight against apartheid, has governed the country since 1994.
But its support has eroded as large inequalities have remained.
The centrist Democratic Alliance (DA) and left-wing Economic Freedom Fighters (EFF) are providing the main challenge.
Apartheid, in place from 1948 to 1994, legalised racial discrimination privileging white people, and land ownership has remained a contentious issue.
The white minority still owns disproportionately more land than the black majority. The EFF has led the charge in trying to change this.