Under the deal, the Qatar sovereign wealth fund will, as a first step, buy half of Enel's stake in 800 megawatts of its existing renewable capacity in South Africa and Zambia.
No financial details were disclosed.
"We will work together to accelerate the creation of an extensive green energy footprint in Sub-Saharan Africa," Enel CEO Francesco Starace said.
Enel Green Power will develop new projects in the region while funding and building will be left to the joint venture.
QIA, one of the world's biggest sovereign wealth funds, has stopped investing in fossil fuel companies and is focusing increasingly on the development of green technologies.
"We believe this investment represents an excellent opportunity to develop and grow a leading renewable energy platform in the region," QIA CEO Mansoor bin Ebrahim Al-Mahmoud said.
Enel, one of the world's biggest clean energy groups, said in November it would spend 160 billion euros in the next 10 years to become a green "super major" and make the company carbon-free by 2050.
It expects to attract another 30 billion euros in investments from parties outside the group under its so-called "stewardship" business model.
(Reporting by Stephen Jewkes, editing by Giulia Segreti and Jane Merriman)
