But it's not just about children who actually have Aids.
Around 12 million children in Africa are 'Aids orphans' - so called because their parents have died from Aids-related illnesses.
In Swaziland, one in 10 families are headed by children because their parents have died of Aids-related diseases.
Delifa is 11-years-old and an Aids orphan.
She's the oldest child in her family and she has to look after her four brothers and sisters.
They live alone in a run-down house in Lilongwe, Malawi.
They don't go to school, they live on one meal a day at the most and struggle to find clothes to wear.
See what life is like for African kids affected by Aids in Newsround on Wednesday 29 January BBC One at 5.25pm.