The office will be headed by Nunu Ntshingila, a former executive at the advertising agency Ogilvy.
"This office will support the significant growth in businesses and people using Facebook," said a statement from the world's biggest social network, which has some 1.4 billion active users worldwide including 120 million in Africa.
"We are inspired by the incredible ways people and businesses in Africa use Facebook to connect," said Nicola Mendelsohn, regional vice president for Facebook.
"Africa is important to Facebook, and this office is a key part of our strategy to expand our investment and presence across (the region). Facebook is already a central part of people's lives in Africa, and with more than a billion people in Africa, we want to do more to help people and businesses connect,”  Mendelsohn said.