The website already provides donors with information on not-for-profit groups in the UK and the US and now wants to do the same in Africa.
Caroline Neligan, director of partnerships and development at GuideStar International, said: "It is a momentous challenge and we can't do it on our own."
The United Nations Economic Commission for Africa will provide the charity information website with data and broker meetings between GuideStar and civil society groups.
GuideStar will eventually build a free web portal for African civil society, showcasing the objectives, activities, needs and finances of not-for-profit organisations.
It is developing similar projects in countries such as Hungary, Germany, India and South Korea.
Jalal Abdel-Latif, chief of the civil society section at Uneca, said: "We want to ensure that the work of these vital organisations is revealed and enabled."