The EU will put up USD 6.75 billion (5 billion euros) and the World Bank USD 1.5 billion to help the long-suffering region, they announced.
The announcement came as UN Secretary General Ban Ki-moon; World Bank President Jim Yong Kim; Andris Piebalgs, the EU development commissioner; and other leading development aid officials were to visit the region.
"The people of the Sahel region desperately need more secure living standards, and our hope is this funding helps build a new path for economic growth in the region," World Bank chief Kim said in a statement.
"This region, in our view, is the most fragile in Africa and its needs in terms of development and security are enormous."
Also Read
"The Sahel is a priority for the EU.... We are determined to continue and increase our support," Piebalgs said.
"Our approach is built on the principle that security is a pre-requisite for growth -- there can be no development without it."
The EU aid is being extended to six countries: Burkina Faso, Mali, Mauritania, Niger, Senegal and Chad.
Mali, where French troops launched an offensive earlier this year to push back Islamist rebels, is the "most fragile country" in the region, Piebalgs said, adding that it would receive 615 million euros in aid.
The UN chief said last week that the Mali crisis highlighted "the need to do more than fight fires in the region -- we need to clear away the problems that could ignite conflict and instability".
The EU describes the Sahel as "one of the poorest regions of the world and it is particularly vulnerable to most of the plagues" that prevent governments providing essential economic, social and political services.
The World Bank is adding the fresh funds to its already substantial programs for the region. The USD 1.5 billion, pledged for the next two years, will go toward developing hydropower and other sources of clean energy to expand irrigation and help agriculture; to communications infrastructure, and to health services.