The Jim Joseph Foundation is giving $17.5 million to the Birthright Israel Foundation.
Much of the gift, $12.5 million, will be used for programming for alumni, Birthright announced last week.
The remaining $5 million will go to support the free 10-day trips to Israel for 18- to 25-year-old Jews.
It was the largest gift by the San Francisco-based Joseph foundation since it started making grants last year.
Birthright has sent some 160,000 Jews to Israel since the program started in 2000, but considerable debate has focused on how effective the trips are in terms of building Jewish identity because there is little follow-up programming for participants.
In a news release, the Birthright foundation said the $12.5 million matching grant will be used to create peer communities for Birthright alumni through “Birthright Israel NEXT,” which will train young adults to help create 15 communities in areas with high concentrations of Birthright alumni.
The program, which will cost $25 million, also will offer programming and opportunities for Jewish involvement.
“Rather than feeling lost in a large Jewish community made up of organizations that are not typically tailored to their needs, Taglit-Birthright Israel alumni will now be empowered by small peer-based communities that fit with their lifestyles,” said Susie Gelman, chair of the Birthright Israel Foundation.
“In these communities, the strong connections to Israel that are sparked on the 10-day trip can be sustained and amplified.”
Birthright estimates that 110,000 of its alumni are from North America.